CVE-2026-89320
`HmacShaCryptor.Hash` never hashed its input
- Risk score
- 59/100
- CVSS
- 8.8 v4.0
- Exploit chance (30 days)
- 0.2%
- Published
- 23 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- HmacShaCryptor.Hash never hashed its input. For any input it returned HMAC_K("") — the MAC of the empty message under the key. Every AES-CBC-HMAC JWE produced or verified by gose therefore carried an authentication tag that is constant per key and independent of the message, removing ciphertext integrity entirely.
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 8.8 high
- Remotely exploitable without logging in
References
Original description
`HmacShaCryptor.Hash` never hashed its input. For any input it returned `HMAC_K("")` — the MAC of the empty message under the key. Every AES-CBC-HMAC JWE produced or verified by gose therefore carried an authentication tag that is constant per key and independent of the message, removing ciphertext integrity entirely.
Last activity 23 Oct 2026. Patch Forecast updates every hour.