# Out-of-bounds write in the Brotli decoder bundled with erl-brotli

Advisory record · `EEF-CVE-2026-111497`

- **Identifiers:** `EEF-CVE-2026-111497`
- **State:** Confirmed
- **Severity:** CVSS 4.0, no score published
- **Critical:** No
- **Weakness (CWE):** [CWE-787](https://cwe.mitre.org/data/definitions/787.html)
- **Tags:** [Memory corruption](https://agentprime.io/advisories/tag/memory-corruption.md)
- **Published:** 22 Oct 2026
- **Updated:** 6 Nov 2026
- **Reviewed by a person:** No

Published by OSV at 22 Oct 2026, 13:35 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `brotli` (Hex): affected `>=0.3.0, <0.3.4`; fixed in `0.3.4`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- Score not published, CVSS 4.0: `CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`, from OSV

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 5 Nov 2026, 20:00 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/EEF-CVE-2026-111497)
- 5 Nov 2026, 20:16 UTC: First seen by agentprime

## Sources

- [OSV: EEF-CVE-2026-111497](https://osv.dev/vulnerability/EEF-CVE-2026-111497)
- <https://github.com/yjh0502/erl-brotli/issues/23>
- <https://cna.erlef.org/cves/CVE-2026-111497.html>
- <https://github.com/yjh0502/erl-brotli/releases/tag/v0.3.4>
- <https://github.com/yjh0502/erl-brotli/commit/1e2af9bebba40ee292abf51e19ac831c2658ca47>
- <https://github.com/yjh0502/erl-brotli/commit/7498e1c743c71a99636e8f897b6b016433830d6d>
- <https://hex.pm/packages/brotli>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/EEF-CVE-2026-111497>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/EEF-CVE-2026-111497/>. Everything for agents: <https://agentprime.io/llms.txt>.