Botan: Heap Buffer Over-read in SM2 Decryption via Undersized C3 Hash Field

Description

Botan is a C++ cryptography library. From version 2.3.0 to before version 3.11.0, during SM2 decryption, the code that checked the authentication code value (C3) failed to check that the encoded value was of the expected length prior to comparison. An invalid ciphertext can cause a heap over-read of up to 31 bytes, resulting in a crash or potentially other undefined behavior. This issue has been patched in version 3.11.0.

Scores

EPSS (exploitation in 30 days)

0.29% · top 78% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.

Weakness

• CWE-125: Out-of-bounds Read (opens in a new tab)All about CWE-125 and its CVEs

Affected products

• randombit · botan

  • affected >= 2.3.0, < 3.11.0

References (1)

• https://github.com/randombit/botan/security/advisories/GHSA-7jj6-4r42-w9h6 (opens in a new tab)x_refsource_CONFIRM

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-32877](https://trackcve.app/badge/CVE-2026-32877.svg)](https://trackcve.app/cve/CVE-2026-32877)

Record last updated 31 Mar 2026, 15:26 UTC.