Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The go-witness module (github.com/in-toto/go-witness) versions before 0.9.1 are affected in the AWS attestor, where verification of EC2 identity documents can wrongly report success if the signature is missing or empty, or if the RSA check fails for any reason. An attacker who can supply a forged identity document could get it accepted as valid. Upgrade to go-witness 0.9.1 or later. The source gives few details on exploitation conditions.
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 |
|---|---|---|---|---|
| 6.9 | Medium | 4.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0020, the 10th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:14 UTC First seen by agentprime
- 31 Oct 2026, 14:14 UTC Confirmed by OSV