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.
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.
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.
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.
Nightmare Eclipse Drops CrowdStrike, Nvidia, Avast Zero-Day Exploits
Researcher Nightmare Eclipse released working zero-day PoCs for Avast, CrowdStrike Falcon, and Nvidia, prompting a Gen patch, CrowdStrike mitigation, and Nvidia investigation.
Security researcher Nightmare Eclipse released three zero-day exploits within a short window: PrettyPrague targeting the Avast sandbox for full system privileges (possibly affecting other GenDigital products including AVG and Norton), FalconFlank exploiting CrowdStrike Falcon Sensor's Office malicious macros remediation feature for privilege escalation, and GreenSection targeting an out-of-bounds memory write in a shared global memory section used by Nvidia user-mode components. GenDigital said it has fixed the Avast issue; CrowdStrike advised disabling the Microsoft Office File Suspicious Macro Removal policy setting; Nvidia said it is actively investigating the PoC. Kevin Beaumont reported that the Avast, CrowdStrike, and Kaspersky exploits work. The researcher previously released the HardBreacher privilege escalation zero-day in Kaspersky endpoint security, patched August 31.
Cosmos EVM Flaw Exploited After Cosmos Labs Knew Every Blockchain Running It Was Vulnerable
Attackers exploited a critical Cosmos EVM balance bug (GHSA-7g4w-cg88-2cq2) to drain funds from six blockchains; fixed in v0.6.2 and v0.7.2.
Cosmos Labs disclosed that a critical balance-handling flaw in the shared Cosmos EVM module (GHSA-7g4w-cg88-2cq2, no CVE) was exploited to drain funds from six blockchains between August 20 and 25, 2026. The bug, reported April 25 and initially judged harmless, lets vesting accounts delegate more than their spendable balance, wrapping balances to roughly 2^256 and triggering unintended mint/burn in reconciliation, potentially halting chains or burning victims' holdings. Fixes shipped in v0.6.2 and v0.7.2 on August 19 as state-breaking coordinated network upgrades; operators who cannot upgrade must halt their chains. The post-mortem notes the team used public silent patching for a fund-threatening issue, contrary to its own bug bounty policy, and that eleven deployments had never registered with its security channels.
Print management outfit PaperCut is under 0-day attack, and it’s drawing customers’ blood
PaperCut print management software is under active zero-day attack, with only an unofficial emergency patch or server shutdown available as mitigation.
Attackers are actively exploiting an unpatched zero-day vulnerability in PaperCut print management software. The only available fix is an unvalidated, unofficial emergency patch, or taking affected servers offline. PaperCut is widely deployed in enterprise environments, giving exposed instances a broad and consequential attack surface.
2026-005: High Vulnerability in the Linux Kernel ("Copy Fail")
Linux kernel flaw CVE-2026-31431 ('Copy Fail', CVSS 7.8) allows unprivileged users to gain root via AF_ALG; a public PoC is out and most distros remain unpatched.
Disclosed on 29 April 2026, CVE-2026-31431 is a local privilege escalation in the Linux kernel's algif_aead module (AF_ALG crypto API), CVSS 7.8, stemming from a 2017 in-place optimisation. By chaining an AF_ALG socket operation with splice(), an unprivileged user can write 4 bytes into an arbitrary page-cache page, e.g. corrupting a setuid binary like /usr/bin/su to obtain a root shell. It affects virtually all kernels built since 2017, including Ubuntu 20.04-24.04, Amazon Linux 2023, RHEL 10.1, and SUSE 16; the mainline fix landed 1 April 2026 but no vendor packages were available as of 30 April. CERT-EU recommends the interim mitigation (disable algif_aead) and blocking AF_ALG via seccomp, prioritising Kubernetes nodes and CI/CD runners.
Linux Kernel ZcopyReaper Vulnerability Lets Local Attackers Gain Root Privileges
Linux kernel RDS zero-copy flaw CVE-2026-43502 (ZcopyReaper) lets unprivileged local users gain root; fix in 7.1-rc3, public PoC published.
CVE-2026-43502, dubbed ZcopyReaper, is a Linux kernel local privilege escalation flaw in the RDS zerocopy send path, present since kernel 4.17, allowing unprivileged local attackers to gain root. NebuSec researcher Yuan Tan demonstrated root escalation on openSUSE kernel 6.4.0-150600.23.100; the fix landed in commit 44b550d88b26 with Linux 7.1-rc3 the first patched mainline release. Exploitation requires CONFIG_RDS and CONFIG_RDS_TCP but not unprivileged user namespaces, and PoC exploit material is publicly released alongside more than 20 other exploitable 2026 kernel CVEs.
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.
PaperCut Replaces Emergency Patches With Fixes for Two Actively Exploited Flaws
PaperCut shipped maintenance releases replacing emergency patches for two actively exploited flaws abused in AI-assisted attacks on 395 organizations.
PaperCut released PaperCut NG/MF versions 26.0.5, 25.0.13 and 24.1.10, superseding Emergency Patch Releases 1-3 for CVE-2026-81578 and CVE-2026-82078, which enable authentication bypass and arbitrary code execution on susceptible instances. GreyNoise and Blackpoint Cyber reported a suspected Russian-speaking actor weaponizing both flaws against at least 395 organizations in 48 countries, concentrated in the U.S. education sector. The campaign used hundreds of AI agents powered by OpenAI's Codex harness and a DeepSeek model, originating from IP 45.142.193.132, and avoided organizations in Russia, China, Hong Kong, Thailand and Iran.
CISA Warns of Citrix NetScaler Authentication Bypass Vulnerability Exploited in Attacks
CISA adds exploited Citrix NetScaler authentication bypass CVE-2026-19490 to the KEV catalog; federal agencies must patch by September 12.
CISA added CVE-2026-19490, a CWE-288 authentication bypass affecting NetScaler ADC and Gateway deployments configured as AAA virtual servers or Gateway services (including SSL VPN, ICA Proxy, and RDP Proxy), to the Known Exploited Vulnerabilities catalog. Citrix released fixes on August 19, 2026; honeypots recorded 56 attack attempts between September 3 and 8 after a public PoC, though no confirmed production compromises have been reported. Affected builds include 14.1 before 14.1-73.32 and 13.1 before 13.1-63.21; newer installations require SAML IdP configuration to be exposed.
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.
Google Chrome Zero-day Vulnerability Exploited in the Wild (CVE-2026-87491)
Google patched actively exploited Chrome V8 out-of-bounds write CVE-2026-87491; CISA added it to KEV with a September 23 patch deadline.
Google fixed 230 Chrome vulnerabilities in its stable channel update, including CVE-2026-87491, an out-of-bounds write in the V8 JavaScript engine being exploited in the wild. The flaw, reported by Jihyeon Jeong of Compsec Lab, Seoul National University, is the seventh Chrome zero-day patched by Google in 2026. It affects Chrome versions before 153.0.8010.36, and CISA added it to the Known Exploited Vulnerabilities Catalog urging patching before September 23, 2026. Users should upgrade to Chrome 153.0.8010.36 (Linux) or 153.0.8010.36/.37 (Windows/Mac); Qualys customers can detect vulnerable assets with QID 388666.
MikroTik patches flaws currently being exploited to take over routers
MikroTik patches six RouterOS flaws, including the actively exploited MikroTrick SSH chain (CVE-2026-67276, CVE-2026-86060) enabling unauthenticated full router takeover.
MikroTik released patches in RouterOS 7.25 beta 3, 7.24.2, 7.23.4, and 6.49.21 for six vulnerabilities found by CERT Polska, affecting the SSH server/client, bandwidth-test service, X.509 handling, and WebFig. CVE-2026-67276, an RSA public-key validation flaw in the SSH server, lets an attacker who knows a username and key modulus authenticate as that user; CVE-2026-86060 then escalates privileges to root via special-character username handling. CERT Polska confirmed attackers are exploiting the chain to take full control of RouterOS devices with SSH exposed to the internet. Shadowserver Foundation scans show over 122,500 devices with internet-reachable SSH, concentrated in Brazil, the US, and Indonesia.