Information Disclosure in PyJWT (CVE-2026-102267)
Summary
Vulnerability in PyJWT (CVE-2026-102267). Confidential information can be exposed externally. Exploitable via PyJWKClient. Mitigation: upgrade to 2.14.0 or later.
Original description
The description as published by the source.
Summary
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…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-102267 has been found in PyJWT.
Attackers can target a specific entry point like PyJWKClient over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.4/10.
What to do: upgrade PyJWT to 2.14.0 or later.
If unsure, ask your IT team or search "PyJWT CVE-2026-102267" on the vendor's site.
CVE-2026-102267 (PyJWT) — CWE-200 / CVSS v3 7.4
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: PyJWKClient / kid / master
Patched: 2.14.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Information disclosure (CWE-200) exists in PyJWT. Attackers reach the vulnerable code path via PyJWKClient without authentication.
Check the vendor advisory for the affected versions of PyJWT. Attack surface: PyJWKClient / kid / master.
Severity: High (CVSS 7.4/10). Confidential information can be exposed externally.
Update to 2.14.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'PyJWT' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'PyJWT' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
PyJWTを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade PyJWT to 2.14.0ステージング環境で 2.14.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- patch security-advisories@github.com
- patch security-advisories@github.com
- web security-advisories@github.com
- web nvd.nist.gov
- web github.com