CVE-2026-104267 Botan: scrypt V-buffer heap overflow on 32-bit from constructor-accepted parameters

Description

Botan is a C++ cryptography library. From 2.7.0 until 3.13.0, Botan's Scrypt implementation on 32-bit platforms computes required memory with unchecked multiplication, allowing attacker-controlled Scrypt parameters to wrap the allocation size and create a buffer smaller than the algorithm subsequently writes. The issue affects systems that enable Scrypt and accept arbitrary parameters from a hostile source, including applications that decrypt attacker-supplied encrypted private keys. A triggering parameter set can cause approximately four gigabytes of Scrypt output to be written past the allocated heap buffer, immediately crashing the process and causing denial of service. Arbitrary code execution is not demonstrated and appears difficult, but cannot be excluded from the overwrite primitive. This issue is fixed in version 3.13.0.

Exploitable with local access to the machine, with an ordinary account and if a user takes an action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Local

Attack complexity

High

Attack requirements

Present

Privileges required

Low

Interaction

Passive

Confidentiality

None

Integrity

None

Availability

High

Confidentiality of other systems

None

Integrity of other systems

None

Availability of other systems

None

Affected products and versions