# PyJWT: Malformed RSA JWK aborts parsing of an entire JWK Set

Advisory record · `GHSA-w6j9-cwv2-h6wq`

- **Identifiers:** `GHSA-w6j9-cwv2-h6wq` · `CVE-2026-102274` · `PYSEC-2026-4152`
- **State:** Confirmed
- **Severity:** CVSS 5.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-755](https://cwe.mitre.org/data/definitions/755.html)
- **Tags:** [CWE-755](https://agentprime.io/advisories/tag/cwe-755.md)
- **Published:** 29 Sept 2026
- **Updated:** 1 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 29 Sept 2026, 18:23 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `pyjwt` (PyPI): affected `>=2.9.0, <2.14.0`; fixed in `2.14.0`

## Machine-written summary

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

> PyJWT versions from 2.9.0 up to but not including 2.14.0 are affected. A malformed RSA JWK inside a JWK Set, with an invalid private exponent and no CRT parameters, raises a plain ValueError that PyJWKSet does not catch, so parsing of the whole set aborts and later valid keys are not loaded. An attacker would need a malformed key to already be present in a set the application parses; the result is an availability failure, not a signature bypass. Upgrade to PyJWT 2.14.0.

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

- 5.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0055, the 46th percentile, on 5 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-w6j9-cwv2-h6wq)

## Sources

- [GitHub Advisory Database: GHSA-w6j9-cwv2-h6wq](https://github.com/advisories/GHSA-w6j9-cwv2-h6wq)
- [OSV: GHSA-w6j9-cwv2-h6wq](https://osv.dev/vulnerability/GHSA-w6j9-cwv2-h6wq)
- <https://github.com/jpadilla/pyjwt/security/advisories/GHSA-w6j9-cwv2-h6wq>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-102274>
- <https://github.com/jpadilla/pyjwt/commit/8915570a0bfda9f0ff0e34e7fb09bdb9d71580cf>
- <https://github.com/jpadilla/pyjwt>
- <https://github.com/jpadilla/pyjwt/releases/tag/2.14.0>

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-w6j9-cwv2-h6wq>, 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-w6j9-cwv2-h6wq/>. Everything for agents: <https://agentprime.io/llms.txt>.