CVE-2026-115774 twisted CVE debrief

Who should care

IMAP4 server administrators and users of the Twisted library should be aware of this vulnerability and take steps to mitigate it. The vulnerability has a significant impact on the availability of the IMAP4 server, and administrators should take immediate action to prevent potential DoS attacks. Additionally, security teams and vulnerability management teams should also be aware of this vulnerability and review their systems for potential exposure.

Why it matters

CVE-2026-115774 is a denial of service vulnerability in the Twisted IMAP4 server that can be exploited by an authenticated client to freeze the process and consume full CPU. IMAP4 server administrators should verify and apply the patch to prevent potential DoS attacks.

• Potential denial of service due to infinite loop
• CPU consumption by malicious SEARCH commands
• Impact on other connections served by the IMAP4 server

Technical summary

The Twisted IMAP4 server is vulnerable to a denial of service attack due to its failure to reject negative literal sizes in SEARCH commands. This can cause the server to enter an infinite loop, consuming full CPU and preventing other connections from being served. The issue arises from the Twisted IMAP4 server's failure to properly validate the literal size in SEARCH commands, allowing an authenticated client to exploit this vulnerability. The vulnerability has a significant impact on the availability of the IMAP4 server, and administrators should take immediate action to mitigate it.

Defensive priority

IMAP4 server administrators should verify and apply the patch to prevent potential DoS attacks.

Recommended defensive actions

• Verify and apply the patch to prevent potential DoS attacks
• Monitor IMAP4 server logs for suspicious activity
• Restrict access to the IMAP4 server to trusted clients
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by the Twisted IMAP4 server's failure to reject negative literal sizes in SEARCH commands, leading to an infinite loop. This issue can be exploited by an authenticated client to freeze the process and consume full CPU.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.