CVE-2026-18149: undici vulnerable to Denial of Service via orphaned RetryHandler response body
Vulnerability summary
CVE-2026-18149 is a medium (CVSS 5.9) vulnerability in nodejs undici. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 41.5% of scored vulnerabilities.
Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3Timeline
- 04-09-2026PublishedVulnerability first disclosed.
- 04-09-2026Last modifiedVulnerability information updated.
Description
undici's retry handler can leave an already-exposed response body pending forever. When a server returns a successful response that declares a Content-Length, sends only part of the body, and closes the connection, the retry handler retries the request. If the retry returns a non-retryable status such as 400, the handler forwards that new response downstream and replaces its internal response stream, but the original response body that the application still holds is never ended or destroyed. As a result calls that read that body never settle, and the configured body timeout does not fire because its timer is tied to the connection parser rather than the orphaned body. An attacker-controlled server can trigger this with two short responses without keeping a connection open, and repeated requests accumulate pending promises and streams that can exhaust application concurrency or memory. This affects undici versions from 7.11.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.
CVSS metrics
7 scores · 7 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · WolfiEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · NpmEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · ChainguardEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.48%
Chance of exploitation in the next 30 days
Percentile
42%
Versus all other CVEs
30-day change
Increase +0.12 pp
From 0.36% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard13 products
- code-server< 4.139.1-r2
- commercial-gitlab-rails-ee-19.1< 19.1.7-r3
- commercial-gitlab-rails-ee-19.2< 19.2.7-r1
- commercial-gitlab-rails-ee-19.3< 19.3.3-r1
- commercial-gitlab-rails-ee-19.4< 19.4.1-r1
Wolfi3 products
- code-server< 4.139.1-r2
- lernaAll versions (No fix recorded) | < 10.0.1-r11
- prism< 5.16.0-r14
Debian1 product
- node-undiciAll versions (No fix recorded) | < 8.10.2+dfsg+~cs3.2.2-1
Nodejs1 product
- undici≥ 7.11.0, < 7.29.1 | ≥ 8.0.0, < 8.10.2
Npm1 product
- undici≥ 7.11.0, < 7.29.1 | ≥ 8.0.0, < 8.10.2
Ubuntu1 product
- node-undiciAll versions (No fix recorded)
Undici1 product
- undici≥ 7.11.0, < 7.29.1 | ≥ 8.0.0, < 8.10.2
7 vendors · 21 products
References
13 links- github.com/nodejs/undici/security/advisories/GHSA-pmjh-fq2x-6v4xREPORTAdvisoryWEBMitigationVendor Advisory
Show all 13 references
- github.com/nodejs/undiciPACKAGE