CVEvulnerability

CVE-2026-43969

2.1 LOW Published 2026-05-11 Modified 2026-10-26 Official page ↗
Status
Modified
Published
2026-05-11
Last modified
2026-10-26
Assigner
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS 4.0 (6b3ad84c-e1a6-4bf7-a703-f496b71e49db)
2.1 LOW — CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
3.2 LOW — CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Weaknesses
CWE-93

Description

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-side Cookie: request header from a list of name-value pairs without validating either field. An attacker who controls the cookie names or values passed to this function can inject ;, ,, CR, LF, or TAB characters into the serialized header. This enables two classes of attack: cookie smuggling within a single header (e.g. injecting ; admin=1 to introduce a phantom cookie that the receiving server treats as authentic) and HTTP request header splitting (injecting CRLF to append arbitrary headers or smuggle a complete second request against a shared upstream proxy). The decoder side (parse_cookie_name/1, parse_cookie_value/1) and setcookie/3 already validate and reject these characters; the encoder alone is missing the check. This issue affects cowlib: from 2.9.0 before 2.21.0.

Affected configurations

• ninenines cowlib (>= 2.9.0 <= 2.16.1)

Related

Weakness · CWE (1)

  • CWE-93 Improper Neutralization of CRLF Sequences weakness

References