CVE-2018-9860

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-04-12 · updated 2026-06-17
Weakness: CWE-193

Description

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

randombit botan: from 1.11.32 before 2.6.0 — fixed in 2.6.0

How to fix

Upgrade to a fixed version: randombit botan 2.6.0. Check the vendor advisory for mitigations.

References

https://botan.randombit.net/security.html
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=7434
https://botan.randombit.net/security.html
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=7434

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