CVE-2026-71380 Erlang CVE debrief

Who should care

Defenders managing Erlang/OTP inets httpd servers, especially those exposed to untrusted networks or with high server utilization, should assess their exposure to this vulnerability and prioritize verification and potential remediation.

Why it matters

CVE-2026-71380 is a denial-of-service vulnerability in Erlang/OTP inets httpd that allows unauthenticated remote attackers to stall server workers, potentially leading to performance degradation or crashes. Defenders should prioritize verifying exposure, especially in environments with high server utilization or exposure to untrusted networks.

• Denial-of-service attacks may occur due to exploitation of this vulnerability.
• Server worker exhaustion could lead to performance degradation or crashes.
• Verification of exposure and configuration is necessary to prevent potential attacks.
• Remediation priority is high for environments with high server utilization or exposure to untrusted networks.

Technical summary

The vulnerability occurs because httpd_request_handler:handle_info/2 cancels the request timeout as soon as a parse step succeeds, which includes the headers, and the clause that handles a decoder asking for more data re-arms the socket with {active, once} without setting any further timer. This allows an attacker to cause a denial of service by sending valid request headers with a large Content-Length and then stalling before the body is complete.

Defensive priority

Defenders should prioritize verifying exposure to this vulnerability, especially those managing Erlang/OTP inets httpd servers, and assess the potential for denial-of-service attacks.

Recommended defensive actions

• Verify the version of Erlang/OTP inets httpd being used and assess exposure to this vulnerability.
• Check if the periodic byte-rate check is configured and consider enabling it if not.
• Monitor server worker utilization and adjust configuration as needed to prevent worker exhaustion.
• Consider implementing compensating controls, such as rate limiting or IP blocking, to mitigate potential attacks.
• Review 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 CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. However, the extent of the vulnerability in versions before OTP 17.0 is unknown.

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.