How severe is GHSA-9v8h-qqgm-4m35?

No CVSS score has been assigned to GHSA-9v8h-qqgm-4m35 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-9v8h-qqgm-4m35?

GHSA-9v8h-qqgm-4m35 affects the following packages: brotli (PyPI), brotlicffi (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-9v8h-qqgm-4m35?

Update brotli to 1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9v8h-qqgm-4m35 is resolved across your whole dependency graph.

How do I detect GHSA-9v8h-qqgm-4m35 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for brotli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-9v8h-qqgm-4m35 if there is no patch (or I can't update yet)?

Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Is GHSA-9v8h-qqgm-4m35 actively exploited in the wild?

No public exploit code has been indexed for GHSA-9v8h-qqgm-4m35 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-9v8h-qqgm-4m35 published, and has it been updated?

GHSA-9v8h-qqgm-4m35 was published on October 22, 2026 and was last updated on October 23, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Brotli: Out-of-bounds write in the Brotli decoder…

Real-World Exposure

2 pkgs affected

🐍brotli🐍brotlicffi

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`brotli`	≥ 1.0.3&&< 1.2.1	1.2.1`pip install --upgrade 'brotli==1.2.1'`
🐍PyPI	`brotlicffi`	≥ 1.0.3&&< 1.2.1.0	1.2.1.0`pip install --upgrade 'brotlicffi==1.2.1.0'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for brotli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update brotli to 1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9v8h-qqgm-4m35 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is GHSA-9v8h-qqgm-4m35 in your dependencies?

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Brotli: Out-of-bounds write in the Brotli decoder ("Node2Shell") also affects the PyPI Brotli packageGHSA-9v8h-qqgm-4m35