What is CVE-2026-1527?

CVE-2026-1527 is a medium-severity vulnerability in Undici, classified under CRLF Injection. CVSS score: 4.6/10. Published 2026-03-12.

How severe is CVE-2026-1527?

Medium severity. CVSS v3 base score is 4.6 out of 10.

Vulnerability in Undici

CVE-2026-1527

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…

Vulnerability class: CRLF Injection

EPSS: 0.000 (1.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N.

Affected products

Undici — versions < 6.24.0; 7.0.0 < 7.24.0, 6.24.0: 7.24.0

Weakness classification (CWE)

CWE-93 — CRLF Injection

References

github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvq
hackerone.com/reports/3487198
cna.openjsf.org/security-advisories.html

Frequently asked questions

What is CVE-2026-1527?: CVE-2026-1527 is a medium-severity vulnerability in Undici, classified under CRLF Injection. CVSS score: 4.6/10. Published 2026-03-12.
How severe is CVE-2026-1527?: Medium severity. CVSS v3 base score is 4.6 out of 10.