CVE-2026-102267
published 2026-09-28CVE-2026-102267: PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated…
PriorityP352critical9.1CVSS 3.1
AVNACLPRNUINSUCHIHAN
EPSS
0.16%
5.0th percentile
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be substituted. This issue is fixed in version 2.14.0.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| jpadilla | pyjwt | < 2.14.0 | 2.14.0 |
| pyjwt_project | pyjwt | < 2.14.0 | 2.14.0 |
| pyjwt_project | pyjwt | >= 0 < 2.14.0 | 2.14.0 |
| ubuntu | pyjwt | — | — |
CVSS provenance
nvdv3.19.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
vendor_ubuntu9.1CRITICAL
vendor_redhat7.4HIGH
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Ubuntu
PyJWT vulnerabilities
vendor_ubuntu·2026-10-15·CVSS 9.1
CVE-2026-102268 [CRITICAL] PyJWT vulnerabilities
Title: PyJWT vulnerabilities
Summary: Several security issues were fixed in PyJWT.
USN-8916-1 fixed vulnerabilities in PyJWT. This update provides the
corresponding fix for PyJWT on Ubuntu 26.10.
Original advisory details:
YuSung Han discovered that PyJWT did not properly validate certain JWK keys
when performing HMAC verification. An attacker could possibly use this
issue to forge authentication tokens. (CVE-2026-102266)
Rohan Das discovered that PyJWT incorrectly handled redirects when fetching
key sets. A remote attacker could possibly use this issue to cause PyJWT
to disclose sensitive information. (CVE-2026-102267)
It was discovered that PyJWT incorrectly recognized certain PEM
representations. An attacker who knew the public key could possibly use
this issue to forge authentica
Ubuntu
PyJWT vulnerabilities
vendor_ubuntu·2026-10-13·CVSS 9.1
CVE-2026-102267 [CRITICAL] PyJWT vulnerabilities
Title: PyJWT vulnerabilities
Summary: Several security issues were fixed in PyJWT.
YuSung Han discovered that PyJWT did not properly validate certain JWK keys
when performing HMAC verification. An attacker could possibly use this
issue to forge authentication tokens. This issue only affected Ubuntu
26.04 LTS. (CVE-2026-102266)
Rohan Das discovered that PyJWT incorrectly handled redirects when fetching
key sets. A remote attacker could possibly use this issue to cause PyJWT
to disclose sensitive information. This issue only affected Ubuntu 22.04
LTS, Ubuntu 24.04 LTS, Ubuntu 26.04 LTS. (CVE-2026-102267)
It was discovered that PyJWT incorrectly recognized certain PEM
representations. An attacker who knew the public key could possibly use
this issue to forge authentication tokens. This is
Red Hat
pyjwt: pyjwt: Verification key substitution via unvalidated JWKS redirects
vendor_redhat·2026-09-28·CVSS 7.4
CVE-2026-102267 [HIGH] CWE-346 pyjwt: pyjwt: Verification key substitution via unvalidated JWKS redirects
pyjwt: pyjwt: Verification key substitution via unvalidated JWKS redirects
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be substituted. This issue is fixed in version 2.14.0.
A flaw was found in PyJWT. When retrieving cryptographic keys from a JSON Web Key Set (JWKS) endpoint, PyJWKClient fails to validate HTTP redirect destinations against trusted domain boundaries. A remote a
GHSA
PyJWT: PyJWKClient follows redirects when fetching JWKS
ghsa·2026-09-29
CVE-2026-102267 [HIGH] CWE-200 PyJWT: PyJWKClient follows redirects when fetching JWKS
PyJWT: PyJWKClient follows redirects when fetching JWKS
### 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.
###
VulDB
jpadilla PyJWT up to 2.13.x PyJWKClient redirect
vuldb·2026-09-28·CVSS 7.4
CVE-2026-102267 [HIGH] jpadilla PyJWT up to 2.13.x PyJWKClient redirect
A vulnerability, which was classified as problematic, was found in jpadilla PyJWT up to 2.13.x. This affects an unknown part of the component PyJWKClient. Such manipulation leads to open redirect.
This vulnerability is uniquely identified as CVE-2026-102267. The attack can be launched remotely. No exploit exists.
You should upgrade the affected component.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-102267 python-jwt: pyjwt: Verification key substitution via unvalidated JWKS redirects [epel-all]
bugzilla·2026-10-13·CVSS 9.1
CVE-2026-102267 [CRITICAL] CVE-2026-102267 python-jwt: pyjwt: Verification key substitution via unvalidated JWKS redirects [epel-all]
CVE-2026-102267 python-jwt: pyjwt: Verification key substitution via unvalidated JWKS redirects [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be s
Bugzilla
CVE-2026-102267 python-jwt: pyjwt: Verification key substitution via unvalidated JWKS redirects [fedora-all]
bugzilla·2026-10-13·CVSS 9.1
CVE-2026-102267 [CRITICAL] CVE-2026-102267 python-jwt: pyjwt: Verification key substitution via unvalidated JWKS redirects [fedora-all]
CVE-2026-102267 python-jwt: pyjwt: Verification key substitution via unvalidated JWKS redirects [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be
Bugzilla
CVE-2026-102267 pyjwt: pyjwt: Verification key substitution via unvalidated JWKS redirects
bugzilla·2026-09-28·CVSS 7.4
CVE-2026-102267 [HIGH] CVE-2026-102267 pyjwt: pyjwt: Verification key substitution via unvalidated JWKS redirects
CVE-2026-102267 pyjwt: pyjwt: Verification key substitution via unvalidated JWKS redirects
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be substituted. This issue is fixed in version 2.14.0.
2026-09-28
Published