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Fencer Vulns
medium 5.3

CVE-2023-49991 json

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

published 2023-12-12 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-53886

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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

Patch / fix

  • espeak-ng Debian 12 1.51+dfsg-10+deb12u1
  • espeak-ng Debian 14, Debian 13 1.51+dfsg-12

debian advisories DEBIAN-CVE-2023-49991

  • espeak-ng Ubuntu 20.04 LTS 1.50+dfsg-6ubuntu0.1
  • espeak-ng Ubuntu 22.04 LTS 1.50+dfsg-10ubuntu0.1
  • espeak-ng Ubuntu Pro 18.04 LTS 1.49.2+dfsg-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2023-49991

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • espeak-ng SLE Module for Desktop Applications 15 SP6, SLE Module for Desktop Applications 15 SP5, openSUSE Leap 15.6 +1 more 1.50-150300.3.3.1

suse advisories SUSE-SU-2024:2632-1

  • espeak-ng Azure Linux 3.0 1.52.0-1

azure linux advisories AZL-34675

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-49991 updated cvss 5.3

espeak-ng: buffer underflow in CountVowelPosition function at synthdata.c

  • Red Hat Enterprise Linux 8 espeak-ng Red Hat Enterprise Linux 9 espeak-ng
    affected: workaround, no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
23 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/espeak-ng/espeak-ng/issues/1825 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.