Bug 2565385

Summary: CVE-2026-118769 botan3: Botan: Integer overflow when reporting block size in FFI can cause memory corruption [fedora-all]
Product: [Fedora] Fedora Reporter: Joel Chamberlain <jochambe>
Component: botan3Assignee: Carlos Rodriguez-Fernandez <carlosrodrifernandez>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: carlosrodrifernandez
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["0e1ced60-d811-4338-ae31-f66f77b1e556"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 2563613    

Description Joel Chamberlain 2026-11-02 20:18:40 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.