netrek-client-cow through 3.3.3 Stack Buffer Overflow via handleSMessage
Affects netrek-client-cow 3.3.3 and earlier when the client connects to the server over plaintext TCP. No vendor rating is given and no fix is listed.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fix or patch referenced
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects netrek-client-cow versions up to and including 3.3.3 Client connection to the server runs over plaintext TCP
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity7.1/10CVSS 7.1
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
CVE-2026-121969 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.1 (high) and affects netrek-client-cow; a fix or patch is referenced.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 19/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fix or patch referenced
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
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.
What to do
Check whether your setup matches what the bug needs.
Affects netrek-client-cow versions up to and including 3.3.3 Client connection to the server runs over plaintext TCPApply the patch listed under Evidence.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- quozl netrek-client-cow
through 3.3.3
Evidence 5
- Patch
- Report
- Repository
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-121969
Is CVE-2026-121969 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A malicious server can send data that the client writes past the end of a fixed-size stack buffer while handling server messages. This can crash the client, causing a denial of service.Source: vulncheck.com
Which versions are affected by CVE-2026-121969?
netrek-client-cow: through 3.3.3.Source: cve.now feed data
Am I affected, and how do I check?
Versions up to and including 3.3.3 are listed as affected, provided the client connects to the server over a plaintext TCP connection. To check, look at the version of netrek-client-cow installed and whether the connection uses plaintext TCP rather than an encrypted transport.Source: vulncheck.com
How do I fix CVE-2026-121969?
No fixed version is listed in the facts provided, so no upgrade target can be named. Check the project's official sources for a newer release that addresses this issue.Source: vulncheck.com