CVE-2026-111497
Google Brotli Unchecked Return Value Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 10 November 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
A buffer overflow vulnerability in the Brotli decoder (c/dec/decode.c) in Google Brotli versions 1.0.3 through 1.2.0 on all platforms allows a remote unauthenticated attacker to corrupt adjacent decoder state memory, disclose sensitive memory contents, cause a denial of service, or potentially execute arbitrary code using a crafted Brotli-compressed stream. Users need to update any Brotli libraries or binaries between 1.0.3 through 1.2.0 to the latest available version: 1.0.10 or 1.1.1 or 1.2.1.
- CVSS 4.0
- 9.2 CRITICALCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 36.03% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 27 October 2026 · due 10 November 2026
- Weakness
- CWE-252, CWE-787
- Source
- cve-coordination@google.com
EPSS moved from 0.5% on 23 October 2026 to 36.0% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
CISA notes
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/google/brotli/releases/tag/v1.2.1 ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-111497
References
- https://github.com/andybalholm/brotli/releases/tag/v1.2.7
- https://nodejs.org/en/blog/vulnerability/october-2026-security-releases#nodejs-brotli-decoder-out-of-bounds-write-permits-remote-code-execution-cve-2026-111497---high
- http://www.openwall.com/lists/oss-security/2026/10/23/25
- http://www.openwall.com/lists/oss-security/2026/10/24/6
- http://www.openwall.com/lists/oss-security/2026/10/26/12
- http://www.openwall.com/lists/oss-security/2026/10/26/13
- http://www.openwall.com/lists/oss-security/2026/10/26/16
- https://broccoli2shell.com
- https://github.com/advisories/GHSA-9v8h-qqgm-4m35
- https://github.com/dotnet/announcements/issues/494
- https://github.com/google/brotli/releases/tag/v1.0.10
- https://github.com/google/brotli/releases/tag/v1.1.1
- https://github.com/google/brotli/releases/tag/v1.2.1
- https://lists.debian.org/debian-lts-announce/2026/10/msg00049.html
- https://patchtheplanet.org/brotli
- https://www.aikido.dev/blog/node2shell-nodejs-brotli-rce-cve-2026-111497
- https://ellio.tech/en/blog/node2shell-cve-2026-111497-rce-on-stock-nodejs-builds/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-111497
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.