CVE-2026-115775 twisted CVE debrief

Who should care

Defenders responsible for Twisted installations should assess their exposure to this vulnerability and prioritize verifying the version of Twisted installed. This includes operators, platform administrators, vulnerability management teams, and security teams who need to ensure that their systems are not vulnerable to this attack. They should also consider the potential impact on system availability if exploited and take steps to mitigate this risk.

Why it matters

CVE-2026-115775 describes an allocation-without-limits vulnerability in Twisted's XML element stream, allowing an unauthenticated remote peer to exhaust server memory. Defenders responsible for Twisted installations should assess their exposure and prioritize verifying the version of Twisted installed.

• Potential denial of service due to memory exhaustion
• Need to verify exposure of Twisted installations to this vulnerability
• Possible impact on system availability if exploited

Technical summary

The vulnerability is caused by the lack of depth or child-count checks in `ExpatElementStream._onStartElement`. This allows an unauthenticated remote peer to exhaust server memory by opening a container element and streaming child elements without closing the container. An element is released only when its end tag arrives, so a container that is never closed retains every child beneath it until the process is killed. The vulnerability affects Twisted installations, and defenders should prioritize verifying the version of Twisted installed and assessing their exposure to this vulnerability.

Defensive priority

Defenders should prioritize verifying exposure of Twisted installations to this vulnerability and assess the potential impact on their systems.

Recommended defensive actions

• Verify the version of Twisted installed and check if it's within the affected range.
• Assess the exposure of Twisted installations to this vulnerability.
• Consider upgrading to a version of Twisted that includes a fix for this vulnerability.
• 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 lack of depth or child-count checks in `ExpatElementStream._onStartElement`. An element is released only when its end tag arrives, so a container that is never closed retains every child beneath it until the process is killed.

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.