VulnerabilityPublished 12 Dec 2023Updated 4 Nov 2025

CVE-2023-49991: espeak-ng

Affects espeak-ngSource CVE Database V5

Not known to be exploited.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Medium

Rated Medium by the CNA (mitre) · No CVSS score from NVD or the CNA

EPSS: 0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Dec 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubespeak-ng/espeak-ng`pkg:github/espeak-ng/espeak-ng`Other threats	Affected =1.52-dev	Fixed in–

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AI-suggested

Users should monitor the vendor's advisories for updates. Until a fix is released, cautious use of espeak-ng 1.52-dev is advised, especially with untrusted input.

Description

A stack buffer underflow vulnerability exists in espeak-ng version 1.52-dev in the function CountVowelPosition within synthdata.c. This flaw could potentially lead to memory corruption issues when processing certain inputs.

Impact

The vulnerability could allow an attacker to cause a stack buffer underflow, potentially leading to application crashes or undefined behavior. There is no evidence of exploitation in the wild or further impact details such as code execution or privilege escalation.

Summary

CVE-2023-49991 identifies a stack buffer underflow vulnerability in espeak-ng 1.52-dev. The issue occurs in the CountVowelPosition function located in synthdata.c. The vulnerability involves improper handling of buffer boundaries, which may cause memory corruption. No CVSS score or detailed impact metrics are provided, and no public exploit or known active exploitation is reported.

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 22:43 UTC

Technical details

References

Community reviews

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