Microsoft September 2026 Patch Tuesday fixes 966 flaws, 2 zero-days
Microsoft's September 2026 Patch Tuesday fixes a record 966 flaws, including two Windows zero-days actively exploited to gain SYSTEM privileges.
Microsoft's September 2026 Patch Tuesday addresses a record 966 vulnerabilities, including 105 rated Critical, 81 of them remote code execution bugs. Two zero-days were actively exploited: a Windows Update Stack link-following flaw and a Windows ALPC heap-based buffer overflow, both allowing local elevation to SYSTEM privileges. The ALPC flaw was reported by Volexity and Proofpoint researchers, while the Update Stack flaw was credited to Romain Deperne and the Microsoft Threat Intelligence Centre. Microsoft shared no details on how the flaws were exploited in attacks.
ZDI-26-557: (Pwn2Own) Amazon Smart Plug Insecure Fallback Information Disclosure Vulnerability
ZDI disclosed a Pwn2Own information disclosure flaw (CVSS 4.3) in Amazon Smart Plug, letting unauthenticated network-adjacent attackers access sensitive information.
The Zero Day Initiative published ZDI-26-557 for an insecure fallback information disclosure flaw in Amazon Smart Plug, demonstrated at Pwn2Own. Unauthenticated network-adjacent attackers can disclose sensitive information on affected installations. ZDI rated the issue CVSS 4.3.
ZDI-26-629: Microsoft Azure Entra ID OAuth Device Code Grant Information Disclosure Vulnerability
Zero Day Initiative disclosed an unauthenticated information disclosure vulnerability (CVSS 5.8) in Microsoft Azure Entra ID's OAuth device code grant flow.
ZDI published advisory ZDI-26-629 describing an information disclosure vulnerability in Microsoft Azure Entra ID related to the OAuth device code grant. Remote attackers can disclose sensitive information without authentication. ZDI assigned a CVSS 3.1 score of 5.8; no CVE identifier is listed in the advisory text.
ZDI-26-703: (0Day) Airbyte SharePoint Connector _get_shared_drive_object Server-Side Request Forgery Information Disclosure Vulnerability
ZDI disclosed an unpatched SSRF information disclosure flaw (CVE-2026-92203, CVSS 7.7) in Airbyte's SharePoint connector, exploitable by authenticated remote users.
The Zero Day Initiative published ZDI-26-703 describing a server-side request forgery vulnerability in the _get_shared_drive_object function of Airbyte's SharePoint connector. Remote attackers can initiate arbitrary server-side requests to disclose information, though valid authentication credentials are required. The flaw carries a CVSS score of 7.7 and is tracked as CVE-2026-92203; it is flagged as a 0day with no vendor patch referenced.
ZDI-26-582: Cisco Identity Services Engine PatchUpdateListener Directory Traversal Information Disclosure Vulnerability
Cisco Identity Services Engine's PatchUpdateListener has an authenticated directory traversal (CVE-2026-20148, CVSS 4.9) enabling sensitive information disclosure.
ZDI advisory ZDI-26-582 describes a directory traversal information disclosure vulnerability in the PatchUpdateListener component of Cisco Identity Services Engine. Remote attackers can disclose sensitive information, but valid authentication is required to exploit the flaw. ZDI assigned a CVSS rating of 4.9 and CVE-2026-20148.
ZDI-26-540: (Pwn2Own) Microsoft Windows win32kfull Use-After-Free Information Disclosure Vulnerability
ZDI discloses CVE-2026-65776, a Pwn2Own win32kfull use-after-free in Windows enabling local information disclosure, CVSS 6.5.
ZDI-26-540 describes a use-after-free vulnerability in Microsoft Windows win32kfull, demonstrated at Pwn2Own, that allows local attackers to disclose sensitive information. Exploitation requires the attacker to first execute low-privileged code on the target system. ZDI assigned a CVSS score of 6.5, tracked as CVE-2026-65776.
ZDI-26-599: Foxit PDF Reader Annotation Use-After-Free Information Disclosure Vulnerability
ZDI published advisory ZDI-26-599 for a use-after-free information disclosure flaw (CVE-2026-57238, CVSS 3.3) in Foxit PDF Reader requiring user interaction.
The Zero Day Initiative released advisory ZDI-26-599 describing a use-after-free vulnerability in Foxit PDF Reader's annotation handling. The flaw allows remote attackers to disclose sensitive information when a target opens a malicious file or visits a malicious page. ZDI rated the issue CVSS 3.3 and assigned CVE-2026-57238.
ZDI-26-573: Linux Kernel KSMBD Response Header Out-Of-Bounds Read Information Disclosure Vulnerability
ZDI disclosed an unauthenticated out-of-bounds read (CVE-2026-68431) in Linux Kernel KSMBD causing sensitive information disclosure, CVSS 9.3.
The Zero Day Initiative published ZDI-26-573 describing an out-of-bounds read in the Linux Kernel KSMBD response header handling. Unauthenticated remote attackers can disclose sensitive information, but only systems with ksmbd enabled are affected. ZDI assigned a CVSS score of 9.3 and the identifier CVE-2026-68431.
ZDI-26-580: Cisco Identity Services Engine Missing Authentication for Critical Function Information Disclosure Vulnerability
ZDI discloses CVE-2026-20190, a missing-authentication flaw in Cisco Identity Services Engine permitting unauthenticated sensitive information disclosure, rated CVSS 7.5.
ZDI-26-580 covers a missing authentication for critical function flaw in Cisco Identity Services Engine. Unauthenticated remote attackers can disclose sensitive information from affected installations. The vulnerability is tracked as CVE-2026-20190 and rated CVSS 7.5. The advisory does not indicate exploitation in the wild.
ZDI-26-601: Foxit PDF Reader Annotation Use-After-Free Information Disclosure Vulnerability
Foxit PDF Reader has a use-after-free vulnerability (CVE-2026-13129, CVSS 3.3) allowing sensitive information disclosure when a user opens malicious content.
ZDI-26-601 describes a use-after-free vulnerability in the annotation feature of Foxit PDF Reader, tracked as CVE-2026-13129 with a CVSS score of 3.3. Successful exploitation allows remote attackers to disclose sensitive information, but requires user interaction such as visiting a malicious page or opening a malicious file. The advisory does not mention any exploitation in the wild.
ZDI-26-682: Linux Kernel IPv6 Neighbour Discovery Uninitialized Memory Information Disclosure Vulnerability
ZDI discloses an uninitialized-memory flaw in Linux kernel IPv6 neighbor discovery (CVE-2026-43040, CVSS 6.0) allowing information disclosure by already-privileged local attackers.
ZDI advisory ZDI-26-682 describes an uninitialized memory vulnerability in the Linux kernel's IPv6 Neighbour Discovery code, tracked as CVE-2026-43040 with a CVSS score of 6.0. Exploitation requires the attacker to already execute high-privileged code on the target, which severely limits practical impact to kernel memory information disclosure. No active exploitation is mentioned.
CVE-2026-77883: Apache Syncope: Information disclosure via one-hop JEXL navigation past the JexlContextBuilder name denylist
Apache Syncope's JEXL template engine permits one-hop navigation past the JexlContextBuilder name denylist, enabling administrator-driven information disclosure.
CVE-2026-77883 is a moderate-severity exposure of sensitive information through data queries in Apache Syncope's syncope-core-provisioning-api module. An administrator can bypass the JexlContextBuilder name denylist using one-hop JEXL navigation to reach sensitive data. Affected versions are 3.0.0-M0 through 3.0.16, 4.0.0-M0 through 4.0.7, and 4.1.0-M0 through 4.1.2.