GHSA-7fh5-64p2-3v2j — medium GitHub Advisory (CVE-2023-44270) in npm/postcss

Description

An issue was discovered in PostCSS before 8.4.31. It affects linters using PostCSS to parse external Cascading Style Sheets (CSS). There may be \r discrepancies, as demonstrated by @font-face{ font:(\r/*);} in a rule.

This vulnerability affects linters using PostCSS to parse external untrusted CSS. An attacker can prepare CSS in such a way that it will contains parts parsed by PostCSS as a CSS comment. After processing by PostCSS, it will be included in the PostCSS output in CSS nodes (rules, properties) despite being originally included in a comment.

Basic information

Type: reviewed
Severity: medium
Advisory on GitHub: Open advisory ↗
Repository advisory: —
Source code: Browse source ↗
Published (advisory): 2023-09-30 00:31:10 UTC
Updated: 2025-11-04 16:45:03 UTC
GitHub reviewed: 2023-10-03 15:04:58 UTC
NVD published: 2023-09-29

Score	Percentile
0.20%	41.55%

CVSS Scores

Base score	Version	Severity	Vector
5.3	3.1	—	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.

Identifiers

Type	Value
GHSA	GHSA-7fh5-64p2-3v2j ↗
CVE	CVE-2023-44270 ↗

CWEs

CWE id	Name
CWE-74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-144	Improper Neutralization of Line Delimiters

Credits

DCKcode (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
npm	postcss	< 8.4.31	8.4.31	—

PostCSS line return parsing error