Vulnerability Description
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persistent subnegotiation buffer until IAC SE is received, without applying a maximum length. Telnet option negotiation occurs before authentication, so an unauthenticated peer can omit the terminator and continuously grow the buffer. The resulting memory exhaustion can terminate the process and every service it hosts. This issue is fixed in version 26.10.0rc1.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/twisted/twisted/commit/073ba878c6c07d569cb61abc5ae76d46eff1b5
- https://github.com/twisted/twisted/commit/5d91cc66a3591faba758a80a1479e0103602fa
- https://github.com/twisted/twisted/pull/12750
- https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1
- https://github.com/twisted/twisted/security/advisories/GHSA-cwm5-jh59-mwxr
FAQ
What is CVE-2026-115778?
CVE-2026-115778 is a vulnerability with a CVSS score of 7.5 (HIGH). Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persi...
How severe is CVE-2026-115778?
CVE-2026-115778 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-115778?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.