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CVE-2026-2581 Not scored

undici is vulnerable to Unbounded Memory Consumption in in Undici's DeduplicationHandler via Response Buffering leads to DoS

This is an uncontrolled resource consumption vulnerability (CWE-400) that can lead to Denial of Service (DoS). In vulnerable Undici versions, when interceptors.deduplicate() is enabled, response data for deduplicated requests could be accumulated in memory for downstream handlers. An attacker-controlled or untrusted upstream endpoint can exploit this with large/chunked responses and concurrent identical requests, causing high memory usage and potential OOM process termination. Impacted users are applications that use Undici’s deduplication interceptor against endpoints that may produce large or long-lived response bodies. PatchesThe issue has been patched by changing deduplication behavior to stream response chunks to downstream handlers as they arrive (instead of full-body accumulation), and by preventing late deduplication when body streaming has already started. Users should upgrade to the first official Undici (and Node.js, where applicable) releases that include this patch.

Exploit probability 0.6%
Published March 12, 2026
Required by Not available
Last source change July 15, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

11 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

related ALSA-2026:7350
related ALSA-2026:7670
related ALSA-2026:7675
related CGA-WGW9-3CHV-8W6P

04 / EVIDENCE

Source records

Open Source Vulnerabilities CVE-2026-2581

This is an uncontrolled resource consumption vulnerability (CWE-400) that can lead to Denial of Service (DoS). In vulnerable Undici versions, when interceptors.deduplicate() is enabled, response data for deduplicated requests could be accumulated in memory for downstream handlers. An attacker-controlled or untrusted upstream endpoint can exploit this with large/chunked responses and concurrent identical requests, causing high memory usage and potential OOM process termination. Impacted users are applications that use Undici’s deduplication interceptor against endpoints that may produce large or long-lived response bodies. PatchesThe issue has been patched by changing deduplication behavior to stream response chunks to downstream handlers as they arrive (instead of full-body accumulation), and by preventing late deduplication when body streaming has already started. Users should upgrade to the first official Undici (and Node.js, where applicable) releases that include this patch.

View original source

05 / REFERENCES

Further evidence