# PyJWT: PyJWKClient follows redirects when fetching JWKS

Advisory record · `GHSA-9v7f-9g4p-ffgj`

- **Identifiers:** `GHSA-9v7f-9g4p-ffgj` · `CVE-2026-102267` · `PYSEC-2026-4144`
- **State:** Confirmed
- **Severity:** CVSS 7.4 High
- **Critical:** No
- **Weakness (CWE):** [CWE-200](https://cwe.mitre.org/data/definitions/200.html) · [CWE-345](https://cwe.mitre.org/data/definitions/345.html) · [CWE-918](https://cwe.mitre.org/data/definitions/918.html)
- **Tags:** [Information disclosure](https://agentprime.io/advisories/tag/info-disclosure.md) · [Server-side request forgery (SSRF)](https://agentprime.io/advisories/tag/ssrf.md) · [CWE-345](https://agentprime.io/advisories/tag/cwe-345.md)
- **Published:** 29 Sept 2026
- **Updated:** 1 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 29 Sept 2026, 23:15 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `pyjwt` (PyPI): affected `<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 before 2.14.0, including 2.13.0, have a flaw in PyJWKClient, which followed HTTP redirects when fetching a JWKS without validating the destination. An attacker who can influence the response from the configured JWKS endpoint could redirect the client to another host, potentially exposing caller-supplied request headers and poisoning the key material used to accept JWTs. Upgrade to PyJWT 2.14.0, which fixes the issue.

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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0016, the 5th percentile, on 6 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-9v7f-9g4p-ffgj)

## Sources

- [GitHub Advisory Database: GHSA-9v7f-9g4p-ffgj](https://github.com/advisories/GHSA-9v7f-9g4p-ffgj)
- [OSV: GHSA-9v7f-9g4p-ffgj](https://osv.dev/vulnerability/GHSA-9v7f-9g4p-ffgj)
- <https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9v7f-9g4p-ffgj>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-102267>
- <https://github.com/jpadilla/pyjwt/commit/0a795b8e1f6ef08f634aa7086fc41cc6d5ce3e56>
- <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-9v7f-9g4p-ffgj>, 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-9v7f-9g4p-ffgj/>. Everything for agents: <https://agentprime.io/llms.txt>.