What is CVE-2026-43969?

CVE-2026-43969 is a low-severity vulnerability in Ninenines Cowlib, classified under CRLF Injection. CVSS score: 3.2/10. Published 2026-05-11.

How severe is CVE-2026-43969?

Low severity. CVSS v3 base score is 3.2 out of 10.

Vulnerability in Ninenines Cowlib

CVE-2026-43969

Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in ninenines cowlib allows HTTP request splitting and cookie smuggling via unvalidated cookie name and value fields. cow_cookie:cookie/1 in cowlib builds a client-…

Vulnerability class: CRLF Injection

EPSS: 0.000 (6.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 3.2 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N.

Affected products

Ninenines Cowlib — versions 2.9.0, f017f8a0ecbffd5033d9ab49bf180186f7a523a7

Weakness classification (CWE)

CWE-93 — CRLF Injection

References

6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Vendor Advisory, third-party-advisory)
6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Third Party Advisory)
6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)

Frequently asked questions

What is CVE-2026-43969?: CVE-2026-43969 is a low-severity vulnerability in Ninenines Cowlib, classified under CRLF Injection. CVSS score: 3.2/10. Published 2026-05-11.
How severe is CVE-2026-43969?: Low severity. CVSS v3 base score is 3.2 out of 10.