randombit Botan up to 3.12.x C API botan_block_cipher_block_size integer overflow

Summaryinfo

A vulnerability was found in randombit Botan up to 3.12.x. It has been classified as critical. The impacted element is the function botan_block_cipher_block_size of the component C API. The manipulation leads to integer overflow. This vulnerability is traded as CVE-2026-118769. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in randombit Botan up to 3.12.x. This issue affects the function botan_block_cipher_block_size of the component C API. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Botan is a C++ cryptography library. From 2.1.0 until 3.13.0, the Botan C API function botan_block_cipher_block_size converted a size_t block size to int without a bounds check. In an application that accepts external algorithm parameter strings and uses the FFI raw ECB mode, an attacker can select the variable-block-size Lion cipher so that the reported size is truncated, the caller allocates insufficient memory, and later block processing causes memory corruption. The C++ API and normally used C API modes such as CBC and CTR are unaffected. This issue is fixed in version 3.13.0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-118769 since 10/28/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 3.13.0 eliminates this vulnerability.

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Productinfo

Vendor

• randombit

Name

• Botan

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12

License

• open-source

Website

• Product: https://github.com/randombit/botan/

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