5.3

CVE-2026-84947: undici vulnerable to response truncation via oversized chunked responses in the dump interceptor

Analyzed
AliasesUBUNTU-CVE-2026-84947DEBIAN-CVE-2026-84947CGA-6jmg-q2c4-6hf4
Published 04-09-2026Last modified 04-09-2026

Vulnerability summary

CVE-2026-84947 is a medium (CVSS 5.3) Improper Input Validation vulnerability in nodejs undici. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 3.7, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (NVD)
EPSS score
0.20%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 5 · Related 2
OPENSUSE-SU-2026:11884-1OPENSUSE-SU-2026:22111-1RHSA-2026:54389RHSA-2026:54438RHSA-2026:66008

Timeline

  1. 04-09-2026
    PublishedVulnerability first disclosed.
  2. 04-09-2026
    Last modifiedVulnerability information updated.

Description

undici's dump interceptor reads and discards a response body up to a configurable maximum size. When a response declares a Content-Length that exceeds the maximum, the interceptor aborts cleanly, but when a response has no Content-Length and is chunked, the interceptor instead signals completion early once the accumulated size reaches the maximum, without pausing or aborting the request. Because the underlying parser keeps delivering body bytes, a second completion signal fires and trips an internal assertion, which aborts the request and tears down the connection. The application is left observing a misleading successful status with an empty or truncated body while the connection has actually been disconnected. This affects undici versions from 7.1.0 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

EPSS trend

Probability

0.20%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.20% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard14 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
Wolfi4 products
  • code-server< 4.139.1-r2
  • lernaAll versions (No fix recorded) | < 10.0.1-r11
  • node-gyp< 13.0.2-r1
  • prism< 5.16.0-r14
Debian1 product
  • node-undiciAll versions (No fix recorded) | < 8.10.2+dfsg+~cs3.2.2-1
Nodejs1 product
  • undici≥ 7.1.0, < 7.29.1 | ≥ 8.0.0, < 8.10.2
Npm1 product
  • undici≥ 7.1.0, < 7.29.1 | ≥ 8.0.0, < 8.10.2
Ubuntu1 product
  • node-undiciAll versions (No fix recorded)
Undici1 product
  • undici≥ 7.1.0, < 7.29.1 | ≥ 8.0.0, < 8.10.2

7 vendors · 23 products

References

12 links
Show all 12 references