BREW-BBOT-CVE-2026-102267 (GHSA-9V7F-9G4P-FFGJ)
Vulnerability from osv_homebrew – Published: 2026-09-30 09:57 – Updated: 2026-09-30 09:57 – Source websiteSummary
PyJWT 2.13.0 PyJWKClient followed HTTP redirects while fetching a JWKS,
without validating the redirect destination. A configured trusted endpoint
could therefore redirect the client to a different host.
Impact
When an application uses PyJWKClient with caller-supplied request headers and
an attacker can influence the configured endpoint's response, the redirected
request could expose those headers and the redirected response could be used as
authoritative key material. This could cause JWKS trust poisoning and, in
affected mixed-configuration applications, forged JWT acceptance. The issue
requires an attacker-influenced redirect from the configured JWKS endpoint; it
is not triggered by a token kid alone.
Affected versions
PyJWT <= 2.13.0.
Fix
The issue is fixed on master in commit
0a795b8e1f6ef08f634aa7086fc41cc6d5ce3e56.
PyJWKClient now disables automatic redirects for JWKS fetches. Regression
tests verify that a redirect is rejected without contacting its destination,
while normal fetches, headers, caching, errors, timeouts, and SSL context remain
covered.
The fix is present in the unreleased development branch. The patched version will be recorded after a released PyJWT 2.x version containing the fix is confirmed.
Credit
Credit: the original reporter of GHSA-9v7f-9g4p-ffgj. Additional redirect header-leak and cache-poisoning evidence from the newer duplicate report GHSA-43g3-98cx-x446 is preserved in the duplicate record and informed this canonical advisory update.
Maintainer update — 2026-09-11
The verified fix for this advisory is included in PyJWT 2.14.0, released on 2026-09-11 and available on PyPI. PyJWT 2.14.0 is the first release containing the fix. This advisory is now published with 2.14.0 recorded as the patched version.
{
"affected": [
{
"ecosystem_specific": {
"fix": null,
"range_state": "affected",
"resource": "pyjwt",
"resource_purl": "pkg:pypi/pyjwt@2.13.0",
"upstream_fixed_in": "2.14.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "bbot",
"purl": "pkg:brew/bbot"
},
"ranges": [
{
"events": [
{
"introduced": "1.1.0.2090"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/pyjwt@2.13.0",
"name": "pyjwt",
"resource": "pyjwt",
"strategy": "registry",
"subject_version": "2.13.0"
}
]
},
"details": "### Summary\n\nPyJWT 2.13.0 `PyJWKClient` followed HTTP redirects while fetching a JWKS,\nwithout validating the redirect destination. A configured trusted endpoint\ncould therefore redirect the client to a different host.\n\n### Impact\n\nWhen an application uses `PyJWKClient` with caller-supplied request headers and\nan attacker can influence the configured endpoint\u0027s response, the redirected\nrequest could expose those headers and the redirected response could be used as\nauthoritative key material. This could cause JWKS trust poisoning and, in\naffected mixed-configuration applications, forged JWT acceptance. The issue\nrequires an attacker-influenced redirect from the configured JWKS endpoint; it\nis not triggered by a token `kid` alone.\n\n### Affected versions\n\nPyJWT `\u003c= 2.13.0`.\n\n### Fix\n\nThe issue is fixed on `master` in commit\n[`0a795b8e1f6ef08f634aa7086fc41cc6d5ce3e56`](https://github.com/jpadilla/pyjwt/commit/0a795b8e1f6ef08f634aa7086fc41cc6d5ce3e56).\n`PyJWKClient` now disables automatic redirects for JWKS fetches. Regression\ntests verify that a redirect is rejected without contacting its destination,\nwhile normal fetches, headers, caching, errors, timeouts, and SSL context remain\ncovered.\n\nThe fix is present in the unreleased development branch. The patched version\nwill be recorded after a released PyJWT 2.x version containing the fix is\nconfirmed.\n\n### Credit\n\nCredit: the original reporter of GHSA-9v7f-9g4p-ffgj. Additional redirect\nheader-leak and cache-poisoning evidence from the newer duplicate report\nGHSA-43g3-98cx-x446 is preserved in the duplicate record and informed this\ncanonical advisory update.\n\n## Maintainer update \u2014 2026-09-11\n\nThe verified fix for this advisory is included in PyJWT 2.14.0, released on 2026-09-11 and available on PyPI. PyJWT 2.14.0 is the first release containing the fix. This advisory is now published with 2.14.0 recorded as the patched version.",
"id": "BREW-bbot-CVE-2026-102267",
"modified": "2026-09-30T09:57:14Z",
"published": "2026-09-30T09:57:14Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9v7f-9g4p-ffgj"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102267"
},
{
"type": "WEB",
"url": "https://github.com/jpadilla/pyjwt/commit/0a795b8e1f6ef08f634aa7086fc41cc6d5ce3e56"
},
{
"type": "PACKAGE",
"url": "https://github.com/jpadilla/pyjwt"
},
{
"type": "WEB",
"url": "https://github.com/jpadilla/pyjwt/releases/tag/2.14.0"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "PyJWT: PyJWKClient follows redirects when fetching JWKS",
"upstream": [
"GHSA-9v7f-9g4p-ffgj",
"CVE-2026-102267"
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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