CVE-2023-49991 Memory corruption in n/a

Medium 5.3 Published 12 Dec 2023 Updated 4 Nov 2025

A stack buffer underflow in espeak-ng allows attackers to cause denial of service or potentially execute arbitrary code via crafted input.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2023-49991?

CVE-2023-49991 is a medium-severity memory corruption vulnerability in n/a, published on 12 Dec 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

Espeak-ng 1.52-dev was discovered to contain a Stack Buffer Underflow via the function CountVowelPosition at synthdata.c.

Weakness: CWE-787

Which versions are affected by CVE-2023-49991?

It affects 1 product.

Products include Espeak-Ng Espeak-Ng.

How do I fix CVE-2023-49991?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2023-49991 being exploited?

There is no known exploitation of CVE-2023-49991 in the wild and no public exploit code.

Sources

Also known as AZL-34675, DEBIAN-CVE-2023-49991, GHSA-vc5p-mv7h-v2mx, UBUNTU-CVE-2023-49991.