How severe is CVE-2026-102269?

CVE-2026-102269 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-102269 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-102269?

CVE-2026-102269 affects Pyjwt Project Pyjwt. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-102269?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-102269 published?

CVE-2026-102269 was published on 2026-09-28 and last updated on 2026-10-06.

CVE-2026-102269

CVE-2026-102269 is a medium-severity vulnerability in Pyjwt Project Pyjwt with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-180.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-180
Affected product: Pyjwt Project Pyjwt
Published: 2026-09-28
Last modified: 2026-10-06

Description

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT signature segment is affected because signature segment decoding accepts characters outside the canonical Base64URL representation. This occurs when non-Base64URL characters are appended to a valid compact JWS signature segment. As a result, base64url_decode produces the same signature bytes for different serialized segments. Consequently, raw-token revocation checks can fail to recognize an equivalent modified token. This issue is fixed in version 2.14.0.

Frequently asked questions

What is CVE-2026-102269?: PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT signature segment is affected because signature segment decoding accepts characters outside the canonical Base64URL representation. This occurs when non-Base64URL characters are appended to a valid compact JWS signature segment. As a result, base64url_decode produces the same signature bytes for different serialized segments. Consequently, raw-token revocation checks can fail to recognize an equivalent modified token. This issue is fixed in version 2.14.0.
How severe is CVE-2026-102269?: CVE-2026-102269 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-102269 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-102269?: CVE-2026-102269 affects Pyjwt Project Pyjwt. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-102269?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-102269 published?: CVE-2026-102269 was published on 2026-09-28 and last updated on 2026-10-06.

References

Affected products (1)

cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*

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