Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Versions of github.com/golang-jwt/jwt/v4 before 4.5.1 can return combined errors from ParseWithClaims where a token is both expired and has an invalid signature. An application that checks only for the expired-token error with errors.Is may therefore accept a token whose signature is invalid. Upgrade to 4.5.1, which returns immediately on dangerous failures such as an invalid signature. If you cannot upgrade, check for all returned errors, handling signature failures before expiry.
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
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 3.1 | Low | 3.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0059, the 48th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:15 UTC First seen by agentprime
- 31 Oct 2026, 14:15 UTC Confirmed by OSV