CVE-2026-111497
Out-of-Bounds Write in Google Brotli Decoder
What happened?
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.
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| github.com/google/brotliGoogle | affected: 1.0.3 to < 1.0.10; affected: 1.1.0 to < 1.1.1; affected: 1.2.0 to < 1.2.1 | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
CISA lists this CVE in its Known Exploited Vulnerabilities catalogue. Added 2026-10-27.
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.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.
Sources and remediation references
- https://www.cve.org/CVERecord?id=CVE-2026-111497
- 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
- https://github.com/andybalholm/brotli/releases/tag/v1.2.7
- 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
- https://github.com/advisories/GHSA-9v8h-qqgm-4m35
- http://www.openwall.com/lists/oss-security/2026/10/23/25
- https://lists.debian.org/debian-lts-announce/2026/10/msg00049.html
- 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
- https://www.aikido.dev/blog/node2shell-nodejs-brotli-rce-cve-2026-111497
- https://broccoli2shell.com
- https://github.com/dotnet/announcements/issues/494
- https://github.com/google/brotli/releases/tag/v1.2.1
- https://github.com/google/brotli/releases/tag/v1.1.1
- https://github.com/google/brotli/releases/tag/v1.0.10
- https://patchtheplanet.org/brotli
- http://www.openwall.com/lists/oss-security/2026/10/26/16
- https://cert-portal.siemens.com/productcert/html/ssa-898633.html
- https://cert-portal.siemens.com/productcert/html/ssa-443410.html
- https://cert-portal.siemens.com/productcert/html/ssa-045512.html