CVE-2026-45623
postcss: PostCSS: Information disclosure and denial of service via crafted CSS input
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · July 28, 2026
Updated · November 4, 2026
Description
A flaw was found in PostCSS, a tool that processes CSS files. An attacker who provides specially crafted CSS input containing a malicious source map comment can cause the system to read arbitrary files from the local filesystem. This can lead to the disclosure of sensitive information, specifically the first few bytes of file content. Additionally, this vulnerability may be exploited to cause a Denial of Service (DoS) by targeting large files, making the system unavailable.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory