# Potential buffer overflow in psd-tools

Advisory record · `GHSA-22jr-vc7j-g762`

- **Identifiers:** `GHSA-22jr-vc7j-g762` · `CVE-2020-10571` · `PYSEC-2020-91`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-754](https://cwe.mitre.org/data/definitions/754.html)
- **Tags:** [CWE-754](https://agentprime.io/advisories/tag/cwe-754.md)
- **Published:** 16 Mar 2020
- **Updated:** 24 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 16 Mar 2020, 22:46 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `psd-tools` (PyPI): affected `>=1.8.37, <1.9.4`; fixed in `1.9.4`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> psd-tools versions 1.8.37 through 1.9.3 are affected. The Cython implementation of RLE decoding did not check malformed PSD input, which can cause a buffer overflow when decoding to PIL.Image or NumPy format. The source does not state what an attacker must do to trigger it, beyond supplying malformed PSD data. Upgrade to psd-tools 1.9.4. Without Cython installed, the overflow does not occur but an IndexError is raised instead.

Written 1 Nov 2026.

## 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

- 9.8 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.018, the 78th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:09 UTC: First seen by agentprime
- 31 Oct 2026, 14:09 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-22jr-vc7j-g762)

## Sources

- [GitHub Advisory Database: GHSA-22jr-vc7j-g762](https://github.com/advisories/GHSA-22jr-vc7j-g762)
- [OSV: GHSA-22jr-vc7j-g762](https://osv.dev/vulnerability/GHSA-22jr-vc7j-g762)
- <https://github.com/psd-tools/psd-tools/security/advisories/GHSA-22jr-vc7j-g762>
- <https://nvd.nist.gov/vuln/detail/CVE-2020-10571>
- <https://github.com/psd-tools/psd-tools/pull/198>
- <https://github.com/psd-tools/psd-tools/commit/fd51f8b4a52bc9c1c06d1035dfdf2cd920e87074>
- <https://github.com/psd-tools/psd-tools>
- <https://github.com/psd-tools/psd-tools/releases/tag/v1.9.4>
- <https://github.com/pypa/advisory-database/tree/main/vulns/psd-tools/PYSEC-2020-91.yaml>

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/GHSA-22jr-vc7j-g762>, 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/GHSA-22jr-vc7j-g762/>. Everything for agents: <https://agentprime.io/llms.txt>.