Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
openssl-encrypt versions before 1.4.0 derive keys with HKDF using no salt and a static info parameter in their key normalization functions. An attacker who can observe or target encrypted data may exploit the predictable derivation, since identical inputs produce identical keys, to weaken security against multi-target attacks. The source gives few details on the exact conditions required. Upgrade to openssl-encrypt 1.4.0 or later; no workaround is listed.
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 |
|---|---|---|---|---|
| 9.3 | Critical | 4.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | CNA (VulnCheck) |
- CISA KEV Not listed.
- EPSS 0.0035, the 28th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:38 UTC First seen by agentprime
- 31 Oct 2026, 14:38 UTC Confirmed by OSV