Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Kas versions 4.8 up to but not including 5.3 have a signature validation flaw: included configuration is processed before repository signatures are checked, so an attacker who controls a referenced repository may be able to replace the key used to verify a tag signature. Exploiting this requires several specific conditions, including a tag reference without a commit ID and a key stored in a repository without a pinned fingerprint. Upgrade kas to version 5.3 or later. As a workaround, pin the expected signature key by its fingerprint.
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 |
|---|---|---|---|---|
| 2.1 | Low | 4.0 | CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0025, the 17th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:40 UTC First seen by agentprime
- 31 Oct 2026, 14:40 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-4vqc-wpwg-vh7j
- OSV: GHSA-4vqc-wpwg-vh7j
- github.com/siemens/kas/security/advisories/GHSA-4vqc-wpwg-vh7j
- github.com/siemens/kas/security/advisories/GHSA-qjwp-hrq6-r26r
- github.com/siemens/kas/commit/4cb4a3d01122ffaec9feaae768a5814092f6f9b5
- github.com/siemens/kas/commit/5b2114becfc154b16ef496d24f8c2191a2297f57
- github.com/siemens/kas