SB20260408104 - Multiple vulnerabilities in Botan

Description

This security bulletin contains information about 3 vulnerabilities.

1) Out-of-bounds read (CVE-ID: CVE-2026-32877)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber

The vulnerability allows a remote attacker to cause a denial of service and disclose sensitive information.

The vulnerability exists due to out-of-bounds read in the SM2 decryption authentication code value (C3) check when processing a crafted SM2 ciphertext with an undersized C3 hash field. A remote attacker can send a specially crafted SM2 ciphertext to cause a denial of service and disclose sensitive information.

The over-read is limited to up to 31 bytes and may result in other undefined behavior.

2) Improper Certificate Validation (CVE-ID: CVE-2026-32884)

CWE-ID: CWE-295 - Improper Certificate Validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to bypass DNS name constraints enforcement.

The vulnerability exists due to improper certificate validation in X.509 certificate path processing when validating a certificate chain with DNS excludedSubtrees constraints and an end-entity certificate that has a mixed-case CN and no subject alternative name. A remote attacker can present a specially crafted certificate to bypass DNS name constraints enforcement.

This issue is relevant when nameConstraints are used to restrict allowable DNS names.

3) Improper Verification of Cryptographic Signature (CVE-ID: CVE-2026-32883)

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to bypass certificate revocation checks.

The vulnerability exists due to improper verification of cryptographic signature in OCSP response verification during X509 path validation when processing OCSP responses. A remote attacker can tamper with an OCSP response body to bypass certificate revocation checks.

Exploitation requires a machine-in-the-middle position between a Botan-based client and an OCSP responder.

Remediation

Install update from vendor's website.

References

• https://github.com/randombit/botan/security/advisories/GHSA-7jj6-4r42-w9h6
• https://github.com/advisories/GHSA-7jj6-4r42-w9h6
• https://github.com/randombit/botan/security/advisories/GHSA-7c3g-7763-ggj5
• https://github.com/randombit/botan/security/advisories/GHSA-9j2j-hqmc-hf5x