4.6

CVE-2026-1527: undici is vulnerable to CRLF Injection via upgrade option

Analyzed
AliasesUBUNTU-CVE-2026-1527DEBIAN-CVE-2026-1527CGA-632g-q9hw-23x6
Published 12-03-2026Last modified 13-03-2026

Vulnerability summary

CVE-2026-1527 is a medium (CVSS 4.6) vulnerability in nodejs undici. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 21.3% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 4.6, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
4.6/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.29%
0%100%
Low · +0.01 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 3 · Related 1
RHSA-2026:7350RHSA-2026:7670RHSA-2026:7675CGA-474R-8WCX-87W5

Timeline

  1. 12-03-2026
    PublishedVulnerability first disclosed.
  2. 13-03-2026
    Last modifiedVulnerability information updated.

Description

ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to: * Inject arbitrary HTTP headers * Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch) The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters: // lib/dispatcher/client-h1.js:1121 if (upgrade) { header += `connection: upgrade\r\nupgrade: ${upgrade}\r\n` }

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

21%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.28% 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, low-privilege account, user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard28 products
  • code-server< 4.110.1-r2
  • gemini-cli< 0.49.0-r4
  • jitsucom-jitsu-console< 2.11.0-r17
  • jitsucom-jitsu-rotor< 2.11.0-r17
  • kibana-8.17< 8.17.10-r13
Wolfi5 products
  • code-server< 4.110.1-r2
  • jitsucom-jitsu-console< 2.11.0-r17
  • jitsucom-jitsu-rotor< 2.11.0-r17
  • langfuse-3-worker< 3.179.1-r1
  • renovate< 43.84.0-r1
Debian1 product
  • node-undiciAll versions (No fix recorded) | < 7.24.5+dfsg+~cs3.2.0-1
Nodejs1 product
  • undici< 6.24.0 | ≥ 7.0.0, < 7.24.0
Npm1 product
  • undici< 6.24.0 | ≥ 7.0.0, < 7.24.0
Ubuntu1 product
  • node-undiciAll versions (No fix recorded)
Undici1 product
  • undici< 6.24.0; 7.0.0 < 7.24.0

7 vendors · 38 products

References

10 links