XS::libbrotli: out-of-bounds write

XS-libbrotli

XS::libbrotli versions before 1.2.1.0 for Perl bundle a brotli library with an out-of-bounds write in the decoder, affecting Perl users

Do this now

Upgrade XS::libbrotli to 1.2.1.0 or later, since earlier Perl-bundled versions have an out-of-bounds write in the decoder.

Fix it

Upgrade to XS-libbrotli 1.2.1.0

First seen: 1 Nov 2026
Last update: 1 Nov 2026, 02:18 UTC
Fixed in: 1.2.1.0
Identifiers: CVE-2026-115946
Source: news

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## XS::libbrotli: out-of-bounds write
Severity: unknown. Patch status: patched.
Affected: XS-libbrotli
Fixed in: 1.2.1.0
Ids: CVE-2026-115946

XS::libbrotli versions before 1.2.1.0 for Perl bundle a brotli library with an out-of-bounds write in the decoder, affecting Perl users

## Steps
1. Search the repo, its CI and infra config for XS-libbrotli. If present, report the version in use and whether it's affected.
2. Fix by release line: XS-libbrotli: 1.2.1.0.

## Fix by release line
| Line | State | Fix | Until then |
|---|---|---|---|
| XS-libbrotli | fixed | 1.2.1.0 | — |

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-115946") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://seclists.org/oss-sec/2026/q4/460
https://pwned.coffee/i/xs-libbrotli-out-of-bounds-write-cve-2026-115946

Receipt

Exploitation: No known exploitation
Fix by release line: Product Affected Fixed in Source
XS-libbrotli before 1.2.1.0 1.2.1.0 CVE record (CNA) checked 1 Nov
Score: No CVSS published yet: severity unknown.
Last checked: 1 Nov 2026, 04:18 UTC

Product	Affected	Fixed in	Source
XS-libbrotli	before 1.2.1.0	1.2.1.0	CVE record (CNA) checked 1 Nov

Sources: KEV – CVE record ✓ Vendor ✓

Sources

seclists.org: CVE-2026-115946: XS::ibbrotli versions before 1.2.1.0 for Perl bundle a brotli library with an out-of-bounds write in the decoder

Wrong fix version, or a source we missed? Send it back to chef@pwned.coffee with the source, and we'll correct it here.

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