CVE-2018-9860: Botan Project Botan

High severity, CVSS 7.5. EPSS: 1.4% chance of exploitation in the next 30 days.

An issue was discovered in Botan 1.11.32 through 2.x before 2.6.0. An off-by-one error when processing malformed TLS-CBC ciphertext could cause the receiving side to include in the HMAC computation exactly 64K bytes of data following the record buffer, aka an over-read. The MAC comparison will subsequently fail and the connection will be closed. This could be used for denial of service. No information leak occurs.

Affected products

• Botan Project Botan: from 1.11.32, before 2.6.0 (fixed in 2.6.0)

Published 2018-04-12. Last modified 2026-06-17.