CVE-2026-34486: Apache Software Foundation Apache Tomcat
CISA added CVE-2026-34486, an actively exploited Apache Tomcat EncryptInterceptor bypass enabling unauthenticated deserialization RCE, to its KEV catalog.
CVE-2026-34486 allows bypass of Apache Tomcat's EncryptInterceptor, a flaw introduced by the fix for padding-oracle issue CVE-2026-29146 in Tribes cluster encryption. CISA added the flaw to the Known Exploited Vulnerability catalog on August 4, 2026, alongside actively exploited Langflow and N-central flaws, with remediation required under BOD 26-04 guidance. Official patches and workarounds are available, and reporting notes unauthenticated remote code execution through Java deserialization on the Tribes receiver port 4000.
CVE-2026-34486: Apache Tomcat EncryptInterceptor Fail-Open Bypass
Technical analysis shows CVE-2026-34486 is a one-line fail-open regression in Tomcat Tribes enabling unauthenticated RCE via Java deserialization.
CVE-2026-34486 is a fail-open regression in Tomcat's Tribes EncryptInterceptor, introduced while fixing the CVE-2026-29146 padding-oracle flaw; Apache rated it Important and NVD scores it 7.5 High. Decryption failures are now forwarded to an unfiltered ObjectInputStream, and public PoC repositories demonstrate unauthenticated RCE on default port 4000 when clustering, the EncryptInterceptor, a reachable receiver and deserialization gadgets are all present. Affected releases 9.0.116, 10.1.53 and 11.0.20 are fixed in 9.0.117, 10.1.54 and 11.0.21; Tomcat 8.5 is unaffected.
CVE-2026-34908: Ubiquiti Networks UniFi OS Server access control ...
CVE-2026-34908, a CVSS 10.0 access-control bypass in Ubiquiti UniFi OS, was added to CISA's KEV catalog amid reported active exploitation.
CISA added CVE-2026-34908 to the Known Exploited Vulnerabilities catalog on June 23, 2026, with remediation due June 26 under BOD 26-04 guidance. The CVSS 10.0 improper access control flaw (CWE-284) in Ubiquiti UniFi OS allows unauthorized system changes without authentication. Multiple news reports referenced by the page describe the max-severity UniFi flaws being exploited in attacks, and an official patch is available.
Attackers Hijack MikroTik Routers Through Internet-Exposed SSH Without Authentication
CERT Polska warns attackers exploit internet-exposed MikroTik SSH for unauthenticated full admin control; attacks observed since at least September 2.
CERT Polska warned on September 5 that attackers exploit MikroTik routers with internet-reachable SSH to gain full administrative control without authentication, calling the two-flaw combination 'MikroTrick'. Successful attacks date to at least September 2; no victim count or attacker identity was disclosed. MikroTik shipped fixed RouterOS releases: 6.49.21, 7.23.4 (with 7.23.5 fixing an IPv6 DHCP regression), 7.24.2, and 7.25beta3. CERT recommends immediate updates, checking for unauthorized configuration changes, and restricting SSH, WWW/WWW-SSL, and bandwidth-test services on unpatched devices.
CISA KEV: Google Chromium V8 Type Confusion Vulnerability — Google Chromium V8 (CVE-2026-85046)
CISA added actively exploited Chromium V8 type confusion CVE-2026-85046 to the KEV catalog, requiring federal mitigation by September 18.
CISA added CVE-2026-85046, a type confusion vulnerability in Google Chromium's V8 JavaScript engine, to the Known Exploited Vulnerabilities catalog. The flaw allows a remote attacker to execute arbitrary code inside the browser sandbox via a crafted HTML page and affects Chromium-based browsers including Google Chrome, Microsoft Edge, and Opera. Federal agencies must apply vendor mitigations by 2026-09-18 under BOD 26-04; CISA notes known ransomware campaign use is currently unknown.
Hackers Chain Two New SonicWall Zero-Day Vulnerabilities
SonicWall warns two zero-days (CVE-2026-83548 SSRF, CVE-2026-83549 post-auth RCE) in SMA1000 appliances are being actively exploited.
A September 1 SonicWall advisory discloses actively exploited zero-days in SMA1000 appliance models 6210, 7210 and 8200v, affecting platform-hotfix versions 12.4.3-03453 and 12.5.0-02835 and older. CVE-2026-83548 (CVSS 10.0) is a pre-authentication SSRF in the Appliance Work Place interface via an unintended alternate access path; CVE-2026-83549 (CVSS 7.8) is post-authentication OS command injection enabling RCE in the Appliance Management Console. SonicWall urges hotfix upgrades, IOC checks with SonicWall support, and re-imaging plus credential and TOTP resets if compromise is found.
CISA Warns Water Utilities: Find Your Exposed PLCs Before Attackers Do
CISA urged water utilities to secure internet-exposed PLCs after July 2026 attacks compromised over 100 US water and wastewater systems, suspected Iran-linked.
CISA's exposure-reduction guidance, published August 21, follows July 2026 attacks in which threat actors remotely accessed PLCs connected directly through cellular modems, changed device IP addresses and passwords, and in some cases disabled alarms and shutdown processes without notifying operators. Iran is the suspected actor, though officials stopped short of formal attribution. CISA recommends routing remote access through centrally managed secure gateways, phishing-resistant MFA, unique credentials, and external scanning of industrial protocols such as Modbus, EtherNet/IP, DNP3, BACnet and OPC UA.
CISA Adds Two Known Exploited Vulnerabilities to Catalog
CISA added actively exploited CVE-2026-76460 (Cisco Identity Services Engine) and CVE-2026-87886 (Acronis Backup) to its KEV catalog.
CISA added two vulnerabilities to its Known Exploited Vulnerabilities Catalog based on evidence of active exploitation: CVE-2026-76460, an incorrect use of privileged APIs flaw in Cisco Identity Services Engine, and CVE-2026-87886, an incorrect default permissions flaw in Acronis Backup. Under Binding Operational Directive 26-04, Federal Civilian Executive Branch agencies must prioritize rapid remediation of KEV vulnerabilities on publicly exposed assets that grant total control post-exploitation, and check whether systems were compromised before patching.
CISA Adds One Known Exploited Vulnerability to Catalog
CISA added actively exploited Google Pixel improper authorization flaw CVE-2026-58704 to its KEV catalog, mandating federal remediation.
CISA added CVE-2026-58704, an improper authorization vulnerability in Google Pixel devices, to the Known Exploited Vulnerabilities Catalog based on evidence of active exploitation. Under BOD 26-04, Federal Civilian Executive Branch agencies must prioritize remediation of KEV-listed vulnerabilities on exposed assets. CISA urges all organizations to prioritize patching KEV entries.
CISA Adds One Known Exploited Vulnerability to Catalog
CISA added CVE-2026-85706, an actively exploited GitLab path traversal flaw, to its KEV Catalog, requiring federal agencies to prioritize patching.
CISA added one vulnerability to its Known Exploited Vulnerabilities Catalog based on evidence of active exploitation: CVE-2026-85706, a path traversal vulnerability in GitLab Community Edition and Enterprise Edition. Under Binding Operational Directive (BOD) 26-04, Federal Civilian Executive Branch agencies must prioritize rapid remediation of KEV-listed vulnerabilities on publicly exposed assets, including checking whether systems were compromised before the patch was applied. While BOD 26-04 binds only FCEB agencies, CISA encourages all organizations to adopt risk-based vulnerability management and prioritize KEV remediations.
CISA Adds Three Known Exploited Vulnerabilities to Catalog
CISA added three actively exploited vulnerabilities — two JFrog Artifactory and one ConnectWise ScreenConnect — to its KEV Catalog.
CISA added CVE-2026-42016 (JFrog Artifactory incorrect authorization), CVE-2026-42018 (JFrog Artifactory improper authentication), and CVE-2026-84869 (ConnectWise ScreenConnect improper privilege management and missing authorization) to the Known Exploited Vulnerabilities Catalog based on evidence of active exploitation. BOD 26-04 requires Federal Civilian Executive Branch agencies to prioritize rapid remediation of such high-risk vulnerabilities on publicly exposed assets and to check for prior compromise. CISA urges all organizations to adopt risk-based vulnerability management and prioritize KEV remediation.
CISA Adds Two Known Exploited Vulnerabilities to Catalog
CISA added two actively exploited MikroTik RouterOS vulnerabilities, CVE-2026-67277 and CVE-2026-86060, to its KEV catalog, mandating federal remediation.
CISA added CVE-2026-67277 (missing authentication for a critical function) and CVE-2026-86060 (improper neutralization of argument delimiters in a command), both in MikroTik RouterOS, to the Known Exploited Vulnerabilities Catalog based on evidence of active exploitation. Under BOD 26-04, Federal Civilian Executive Branch agencies must prioritize rapid remediation of these flaws on publicly exposed assets that grant total control post-exploitation. Agencies are also required to check whether systems were compromised before patches were applied.
New ‘ShieldCrash’ Zero-Day Exploit Targets Microsoft Defender
Researcher Nightmare Eclipse released ShieldCrash, a Microsoft Defender zero-day PoC bypassing ShieldBreak patches to gain System privileges on Windows.
The researcher known as Nightmare Eclipse released a PoC zero-day exploit dubbed ShieldCrash against Microsoft Defender on fully patched Windows systems. The exploit grants arbitrary file read with System privileges and can be used to drop the SAM database. It bypasses Microsoft's September 3 fixes for ShieldBreak (CVE-2026-69414), which itself bypassed patches for the RoguePlanet race condition (CVE-2026-50656). Microsoft has been contacted for comment and has not yet responded.
CISA Adds Four Known Exploited Vulnerabilities to Catalog
CISA added four actively exploited vulnerabilities—Fortinet buffer overflow, Citrix NetScaler and Cisco auth bypasses, and a Chromium V8 write—to the KEV Catalog.
CISA added CVE-2025-25249 (Fortinet heap-based buffer overflow), CVE-2026-19490 (Citrix NetScaler authentication bypass), CVE-2026-87491 (Google Chromium V8 out-of-bounds write), and CVE-2026-20079 (Cisco Firewall Management Center authentication bypass) to its Known Exploited Vulnerabilities Catalog based on evidence of active exploitation. Under Binding Operational Directive 26-04, Federal Civilian Executive Branch agencies must prioritize rapid remediation of these high-risk vulnerabilities on exposed assets and verify whether systems were compromised before patching. CISA encourages all organizations to adopt risk-based vulnerability management and prioritize KEV Catalog remediation.
Windows Defender ShieldCrash 0-Day Lets Attackers Read Arbitrary Files as SYSTEM
Unpatched Windows Defender zero-day 'ShieldCrash' PoC lets local attackers read arbitrary files as SYSTEM, apparently bypassing the CVE-2026-69414 patch.
Researcher MSNightmare published a skeleton proof-of-concept for 'ShieldCrash', an unpatched Microsoft Defender flaw enabling arbitrary file reads with SYSTEM privileges that reportedly persists on supported Windows versions after September 2026 updates. It appears to bypass the recent fix for the Malware Protection Engine elevation-of-privilege flaw CVE-2026-69414 (ShieldBreak), patched in engine version 1.1.26080.3. SYSTEM-level file disclosure could expose credentials, application secrets and registry hives and support post-compromise reconnaissance. No active exploitation is confirmed and Microsoft had issued no specific patch or mitigation at disclosure time.
Microsoft discloses two actively exploited zero-days among 974 vulnerabilities
Microsoft patches 974 flaws in record Patch Tuesday, including two actively exploited Windows zero-days enabling privilege escalation.
Microsoft's largest-ever Patch Tuesday addresses 974 vulnerabilities, with CVE-2026-81963 (Windows Update Stack) and CVE-2026-85880 (Windows Advanced Local Procedure Call) exploited before disclosure. Both zero-days carry CVSS 7.8 ratings and allow privilege escalation. More than 10% of the defects are rated critical, and researchers attribute the record volume to AI-assisted vulnerability discovery without a matching rise in active exploitation.
CISA Adds Four Known Exploited Vulnerabilities to Catalog
CISA added four actively exploited vulnerabilities to its KEV catalog, covering Adobe Commerce/Magento, Microsoft Windows, and N-able N-central.
CISA added CVE-2026-75650 (Adobe Commerce and Magento, improper neutralization in a template engine), CVE-2026-81963 (Microsoft Windows link following), CVE-2026-85880 (Microsoft Windows heap-based buffer overflow), and CVE-2026-86218 (N-able N-central static code injection) to the Known Exploited Vulnerabilities Catalog based on evidence of active exploitation. Under Binding Operational Directive 26-04, federal civilian agencies must prioritize rapid remediation of KEV-listed vulnerabilities on exposed assets that grant total control post-exploitation and check for pre-patch compromise. All organizations are encouraged to prioritize these flaws in risk-based patching.
Hackers Are Probing PaperCut Servers, and 47% Still Have No Patch
PaperCut pre-auth RCE CVE-2026-81578 actively exploited; 47% of tracked installs unpatched and exposed to remote code execution.
Huntress confirmed active exploitation of a pre-authentication RCE flaw in PaperCut (CVE-2026-81578), chainable with CVE-2026-82078 to achieve SYSTEM-level code execution via PaperCut's Application Server. Observed attacks focused on short reconnaissance (whoami, ver, tasklist) with no persistence, but a malicious Java class dropping into the installation directory leaves the jdbc:derby:memory:pwn breadcrumb. Roughly 47% of ~2,500 tracked installations run version 23 or earlier with no patch yet available.
CISA Adds One Known Exploited Vulnerability to Catalog
CISA added CVE-2026-85046, a Google Chromium V8 type confusion vulnerability with evidence of active exploitation, to its KEV Catalog.
On September 4, 2026, CISA added one vulnerability to the Known Exploited Vulnerabilities Catalog: CVE-2026-85046, a type confusion flaw in Google Chromium's V8 engine, added based on evidence of active exploitation. CISA notes type confusion is a frequent attack vector and poses significant risk to the federal enterprise. Under Binding Operational Directive 26-04, Federal Civilian Executive Branch agencies must prioritize remediation of KEV vulnerabilities on exposed assets and check for pre-patch compromise; all organizations are urged to prioritize the patch.
Rogue ScreenConnect Installations Across Unrelated Hosts Suggest Worm-Like Activity
Huntress observed rogue ScreenConnect deployments with worm-like VBScript propagation across unrelated organizations, prompting a ConnectWise advisory on file transfer behavior.
Huntress identified multiple incidents in late August 2026 where social engineering led to rogue ScreenConnect remote access clients deployed on victim machines, which then spawned wscript.exe to run four VBScript payloads (1.vbs through 4.vbs) for profiling, telemetry collection, and persistence via a WindowsServiceHost Run key. Modified ScreenConnect clients propagated the VBScript chain to connected endpoints, creating worm-like spread. ConnectWise published an advisory on September 3, 2026, confirming an issue affecting file transfer behavior in both cloud and on-premises ScreenConnect deployments, with a CVE and fix expected within the week; partners were advised to review and disable TransferFiles permissions in the interim.
BGP Hijack Delivers Malicious Virtualizor Update That Establishes Persistent Root Access
Attackers used a BGP hijack to divert Softaculous traffic and push a malicious Virtualizor update granting root persistence on some hypervisors.
Virtualizor reported that a BGP hijack between August 28 20:57 UTC and August 30 06:10 UTC diverted Softaculous update traffic to an attacker-operated server holding a valid Let's Encrypt certificate. Installations checking for updates during the window could receive a malicious package that added an attacker SSH key to root, created a proxyuser account, and installed a Java payload persisted via a systemd service. Hosting provider AlbaHost confirmed 5 of its 34 Virtualizor hypervisors were root-compromised. Virtualizor shipped Patch 9 with a Security Analyzer on September 1, but cryptographic package signing remains future work.
CISA Adds Seven Known Exploited Vulnerabilities to Catalog
CISA added seven actively exploited vulnerabilities to its KEV catalog, including SonicWall SMA1000 SSRF and command injection flaws.
CISA added seven vulnerabilities with evidence of active exploitation to its Known Exploited Vulnerabilities catalog on September 2, 2026. The additions cover Sangoma Switchvox SQL injection (CVE-2026-9586), Kludex Starlette request smuggling (CVE-2026-48710), Kestra OS command injection (CVE-2026-49869), BerriAI LiteLLM (CVE-2026-59822) and JFrog Artifactory (CVE-2026-82329) authentication flaws, and SonicWall SMA1000 SSRF (CVE-2026-83548) and command injection (CVE-2026-83549) vulnerabilities. Under BOD 26-04, federal civilian agencies must prioritize rapid remediation of KEV-listed vulnerabilities on publicly exposed assets.
Attackers plant remote access tools on compromised PaperCut servers
Attackers chained two PaperCut NG/MF zero-days for unauthenticated access, installing SimpleHelp and AnyDesk remote access tools on compromised servers.
An ongoing campaign exploits chained zero-days CVE-2026-81578 (improper access control) and CVE-2026-82078 (unsafe dynamic class loading) in internet-facing PaperCut NG and MF Application Servers, enabling authentication bypass and arbitrary Java bytecode execution. Post-compromise activity includes user and domain enumeration, payload download from sendit.sh, and silent installation of SimpleHelp and AnyDesk for redundant remote access; Defused observed CVE-2026-81578/CVE-2026-82078 exploit activity in honeypots since August 29, including data theft via Derby database dumps. Emergency patches were released August 28 and August 30, but 47% of roughly 2,500 PaperCut installs tracked by Huntress run v23 or older, for which no patch is available.
PaperCut Zero-Day Under Active Attack: Emergency Patch Released
PaperCut warns that a zero-day in NG and MF print management products is being actively exploited, shipping emergency patches with no CVE assigned yet.
PaperCut Software confirmed active exploitation of a zero-day affecting PaperCut NG and MF, with confirmed customer incidents, and released emergency patches on Friday ahead of technical details or a CVE assignment. The company urges customers to restrict web access to trusted IP addresses, disconnect application servers from the internet, and watch for indicators including tampered or truncated server.log files, database error strings, and suspicious activity involving pc-app.exe. The article recalls the May 2023 exploitation of CVE-2023-27350 and CVE-2023-27351 by the financially motivated Lace Tempest group, a Clop ransomware RaaS affiliate, though no attacker attribution has been given for the current campaign.
Threat Brief: OWASSRF Vulnerability Exploitation
Unit 42 details active exploitation of Exchange SSRF flaws CVE-2022-41080/CVE-2022-41082 via the OWASSRF method, deploying the SilverArrow PowerShell backdoor.
Unit 42 documents OWASSRF, an exploit chain combining CVE-2022-41080 and CVE-2022-41082 to achieve remote code execution on Microsoft Exchange via Outlook Web Access, bypassing Microsoft's ProxyNotShell mitigations. Active exploitation was observed in late November and early December 2022, affecting at least eight organizations. Attackers authenticated to Exchange, then executed a PowerShell backdoor tracked as SilverArrow to create admin accounts, install AnyDesk, tunnel RDP via PuTTY Link, and dump LSASS memory for credential theft. Exploitation is isolated rather than mass-scale because authentication is required.