UBUNTU-CVE-2026-104267: Medium severity ubuntu/botan vulnerability

Published Nov 9, 2026
·
Updated

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.

Affected Software

6 affected components
ubuntu/botan*
ubuntu/botan*
ubuntu/botan*
ubuntu/botan*
ubuntu/botan3*
ubuntu/botan3*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Botan to a version that resolves this vulnerability.

    Fixed in 3.13.0

Event History

Nov 9, 2026
CVE Published
via OSV·12:00 AM
Data Sourced
via OSV·12:00 AM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

Which deployments are exposed to this issue?

The issue affects Botan versions from 2.7.0 up to, but not including, 3.13.0 on 32-bit platforms. Exposure requires that Scrypt is enabled and that the application accepts Scrypt parameters from a hostile source.

2

What must an attacker be able to do to trigger the flaw?

An attacker needs to supply crafted Scrypt parameters that cause the required-memory calculation to overflow on a 32-bit system. One identified exposure path is an application decrypting an attacker-supplied encrypted private key.

3

What is the likely impact of successful exploitation?

A triggering parameter set can write roughly four gigabytes of Scrypt output beyond an undersized heap allocation, immediately crashing the process and causing denial of service. Arbitrary code execution has not been demonstrated; it appears difficult but cannot be ruled out.

4

What version fixes the issue?

The issue is fixed in Botan 3.13.0.

Contact

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