CVE-2026-42784
A flaw was found in sequoia-openpgp. The library incorrectly infers key flags for older certificates when a key flags subpacket is missing, leading to a discrepancy in how key capabilities are viewed. This key flag confusion allows an attacker to bypass the back-signature check. Consequently, an attacker can illegitimately bind an arbitrary subkey to their own certificate and forge signatures, completely compromising cryptographic integrity.
- Published Sep 16, 2026
- CVSS 7.4 high
- 0.2% chance of exploitation in the next 30 days (EPSS)
- A fix is available