CVE-2026-85024: undici vulnerable to Denial of Service via unhandled error in WebSocket permessage-deflate decompression
Vulnerability summary
CVE-2026-85024 is a medium (CVSS 5.9) Uncaught Exception vulnerability in nodejs undici. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 35.5% 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 4 · Related 1Timeline
- 04-09-2026PublishedVulnerability first disclosed.
- 04-09-2026Last modifiedVulnerability information updated.
Description
undici bundles a WebSocket client whose permessage-deflate size-limit cleanup removes all listeners from the internal zlib inflate stream, including its error listener, while that stream can still emit. When a remote peer sends a compressed payload that crosses the built-in 128 MiB decompressed-payload limit and then contains a malformed DEFLATE byte, the inflate stream emits a data error with no listener attached, which Node.js treats as a fatal unhandled error and terminates the entire process. Exploitation is remote and unauthenticated, requires no application mistake, and is asymmetric, since roughly 130 KB on the wire expands past the limit and crashes the process, and reconnecting can repeat the crash. This affects undici versions from 6.25.0 up to 6.28.1, from 7.28.0 up to 7.29.1, and from 8.1.0 up to 8.10.2. Users should upgrade to undici 6.28.1, 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
0.41%
Chance of exploitation in the next 30 days
Percentile
36%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.41% 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
- actions-runner< 2.337.0-r2
- code-server< 4.139.1-r2
- commercial-gitlab-rails-ee-19.4< 19.4.1-r1
- commercial-gitlab-rails-ee-fips-19.4< 19.4.1-r1
- homepage< 2.4.0-r1
Wolfi6 products
- code-server< 4.139.1-r2
- lernaAll versions (No fix recorded) | < 10.0.1-r11
- prism< 5.16.0-r14
- pulumi-language-nodejs< 3.265.0-r3
- renovate< 44.131.0-r1 | < 44.133.0-r0 | < 44.118.2-r0 | < 44.119.1-r0
Debian1 product
- node-undiciAll versions (No fix recorded) | < 8.10.2+dfsg+~cs3.2.2-1
Nodejs1 product
- undici≥ 6.25.0, < 6.28.1 | ≥ 7.28.0, < 7.29.1 | ≥ 8.1.0, < 8.10.2
Npm1 product
- undici≥ 6.25.0, < 6.28.1 | ≥ 7.28.0, < 7.29.1 | ≥ 8.1.0, < 8.10.2
Ubuntu1 product
- node-undiciAll versions (No fix recorded)
Undici1 product
- undici≥ 6.25.0, < 6.28.1 | ≥ 7.28.0, < 7.29.1 | ≥ 8.1.0, < 8.10.2
7 vendors · 24 products
