What’s Vulnerable › Vulnerabilities

CVE-2026-115776: Twisted: Unauthenticated Remote Denial of Service in the Twisted IRC Server via an Unbounded Line Buffer

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-23 · updated 2026-10-30
• Weakness: CWE-400

Description

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.words.protocols.irc.IRC.dataReceived retains all bytes received without a line feed in its per-connection buffer and applies no maximum line length. The twisted.words.service.IRCUser server subclass inherits this behavior, and buffering occurs before PASS, NICK, or USER authentication commands. An unauthenticated connection can continuously grow the buffer until the shared server process runs out of memory and drops all users. This issue is fixed in version 26.10.0rc1.

Affected products

• twisted: before 26.10.0rc1

References

• https://github.com/twisted/twisted/commit/01f8cff7753c1edac132380b2ea939fa6bdbab30
• https://github.com/twisted/twisted/commit/ac90fb7b0ab73688a581fcd9a7c0577ec8ca3059
• https://github.com/twisted/twisted/pull/12771
• https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1
• https://github.com/twisted/twisted/security/advisories/GHSA-53xc-49m8-p798

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