Buffer overflow in Quozl Netrek-Client-Cow
CVE-2026-121969
netrek-client-cow through 3.3.3 contains a stack-based buffer overflow vulnerability in handleSMessage() in short.c that allows malicious servers to overflow a 100-byte stack buffer by sending oversized SP_S_MESSAGE packets. A malicious Netrek server or man-in-the-middle on the plaintext TCP connection can send overlong or unterminated message bodies to write server-controlled bytes onto the stack and crash the client.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/quozl/netrek-client-cow (product)
- github.com/quozl/netrek-client-cow/blob/3.3.3/short.c (technical-description)
- Patch Commit (patch)
- github.com/quozl/netrek-client-cow/issues/11 (issue-tracking)
- VulnCheck Advisory: netrek-client-cow through 3.3.3 Stack Buffer Overflow via handleSMessage (third-party-advisory)
Frequently asked questions
- What is CVE-2026-121969?
- CVE-2026-121969 is a medium-severity vulnerability in Quozl Netrek-Client-Cow, classified under Stack-based Buffer Overflow. CVSS score: 6.5/10. Published 2026-11-04.
- How severe is CVE-2026-121969?
- Medium severity. CVSS v3 base score is 6.5 out of 10.