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TI-2026-26828 Aliases CVE-2026-34580

Botan has a certificate authentication bypass due to trust anchor confusion

Priority MEDIUM 48CWE-295Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Spoofing
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 1 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-295.

Summary

Botan is a C++ cryptography library. In 3.11.0, the function Certificate_Store::certificate_known had a misleading name; it would return true if any certificate in the store had a DN (and subject key identifier, if set) matching that of the argument. It did not check that the cert it found and the cert it was passed were actually the same certificate. In 3.11.0 an extension of path validation logic was made which assumed that certificate_known only returned true if the certificates were in fact identical. The impact is that if an end entity certificate is presented, and its DN (and subject key identifier, if set) match that of any trusted root, the end entity certificate is accepted immediately as if it itself were a trusted root. , This vulnerability is fixed in 3.11.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00461 40th percentileScored 2026-11-07
Fix Partial botan (randombit): 3.11.1Red Hat: 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
randombitbotan3.11.0 to before 3.11.13.11.1Patch availableCNA
  • botan Vendorrandombit Affected 3.11.0 to before 3.11.1 Fixed in 3.11.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:botan_project:botan:3.11.0:*:*:*:*:*:*:*3.11.0Vulnerablerandombit
  • cpe:2.3:a:botan_project:botan:3.11.0:*:*:*:*:*:*:* Versions 3.11.0 Vulnerable ·randombit

Remediation

  • Fix · CNA botan (randombit) Fixed in 3.11.1

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix planned: Will not fix

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34580

References

Advisory 1

  • TI-2024-33818 Botan before 3.6.0, when certain GCC versions are used, has a compiler-induced… CVSS 3.1MEDIUM 5.9
  • TI-2024-33817 Botan before 3.6.0, when certain LLVM versions are used, has compiler-induced… CVSS 3.1MEDIUM 5.9
  • TI-2016-02004 Integer overflow in the PointGFp constructor in Botan before 1.10.11 and 1.11.x before… CVSS 3.0CRITICAL 9.8
  • TI-2016-02005 Heap-based buffer overflow in the P-521 reduction function in Botan 1.11.x before 1.11.27… CVSS 3.0CRITICAL 9.8
  • TI-2016-07479 In Botan 1.8.0 through 1.11.33, when decoding BER data an integer overflow could occur… CVSS 3.0CRITICAL 9.8
  • TI-2021-06410 In Botan before 2.17.3, constant-time computations are not used for certain decoding and… CVSS 3.1CRITICAL 9.8
See all 34 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences