CVE-2026-115778
Twisted: Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-400 CWE-770 |
| Vendor | twisted |
| Product | twisted |
| Published | Oct 23, 2026 |
| Last Updated | Oct 23, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
twisted / twisted
< 26.10.0rc1
References
github.com: https://github.com/twisted/twisted/security/advisories/GHSA-cwm5-jh59-mwxr github.com: https://github.com/twisted/twisted/pull/12750 github.com: https://github.com/twisted/twisted/commit/073ba878c6c07d569cb61abc5ae76d46eff1b529 github.com: https://github.com/twisted/twisted/commit/5d91cc66a3591faba758a80a1479e0103602facc github.com: https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1