postcss: PostCSS: Information disclosure via crafted sourceMappingURL

A flaw was found in PostCSS. A remote attacker can exploit this vulnerability by providing a specially crafted sourceMappingURL when a specific configuration the 'from' parameter is not set. This can cause the application to read and expose unintended source-map files, potentially revealing...

NPM: PostCSS: incomplete fix of GHSA-6g55-p6wh-862q — attacker-controlled sourceMappingURL reads arbitrary .map files when `from` is unset

NPM: PostCSS: incomplete fix of GHSA-6g55-p6wh-862q — attacker-controlled sourceMappingURL reads arbitrary .map files when from is unset vulnerability discovered by ? in WordPress Npm postcss versions = 8.5.22...

PostCSS: incomplete fix of GHSA-6g55-p6wh-862q — attacker-controlled sourceMappingURL reads arbitrary .map files when `from` is unset

Summary The fix for GHSA-6g55-p6wh-862q added a guard in lib/previous-map.js PreviousMap.loadFile that restricts an attacker-controlled sourceMappingURL from a CSS comment to a .map extension and, for untrusted maps, rejects .. traversal and absolute paths. The traversal/absolute rejection is...

Directory Traversal

Overview org.webjars.npm:postcss is a PostCSS is a tool for transforming styles with JS plugins. Affected versions of this package are vulnerable to Directory Traversal in the PreviousMap.loadFile method of lib/previous-map.js, which nests its traversal guard inside an if cssFile branch that is...

CVE-2026-69153

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.19, if from is unset, an attacker can cause PreviousMap.loadFile to read an unintended source-map file by supplying an absolute or directory-traversal...

CVE-2026-69153

CVE-2026-69153 (PostCSS) affects PostCSS prior to 8.5.19. If the option from is unset, an attacker can cause PreviousMap.loadFile() to read an unintended source-map file by supplying an absolute or directory-traversal sourceMappingURL, exposing the map’s sources and sourcesContent. The issue is f...

CVE-2026-69153 PostCSS: incomplete fix of CVE-2026-45623 — attacker-controlled sourceMappingURL reads arbitrary .map files when `from` is unset

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.19, if from is unset, an attacker can cause PreviousMap.loadFile to read an unintended source-map file by supplying an absolute or directory-traversal...

Linux Distros Unpatched Vulnerability : CVE-2026-45623

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prio...

CVE-2026-45623

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the / sourceMappingURL=PATH / comment from any CSS string passed to process and dereferences PATH against the...

CVE-2026-45623

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the / sourceMappingURL=PATH / comment from any CSS string passed to process and dereferences PATH against the...

EUVD-2026-49376

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the / sourceMappingURL=PATH / comment from any CSS string passed to process and dereferences PATH against the...

CVE-2026-45623

PostCSS vulnerability CVE-2026-45623 affects versions up to 8.5.11. The PreviousMap parses the /*# sourceMappingURL=PATH */ comment from CSS, dereferencing PATH against the local filesystem without scheme, allowlist, or traversal checks. An attacker-controlled CSS input can cause the host process...

CVE-2026-45623 PostCSS: Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the / sourceMappingURL=PATH / comment from any CSS string passed to process and dereferences PATH against the...

CVE-2026-45623 PostCSS: Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. In versions 8.5.11 and prior, the PreviousMap parses the / sourceMappingURL=PATH / comment from any CSS string passed to process and dereferences PATH against the...

Directory Traversal

Overview postcss is a PostCSS is a tool for transforming styles with JS plugins. Affected versions of this package are vulnerable to Directory Traversal via the process function. An attacker can access arbitrary files and obtain the first 10 bytes of their contents by supplying a crafted...

NPM: PostCSS: Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments

NPM: PostCSS: Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments vulnerability discovered by ? in WordPress Npm postcss versions = 8.5.11...

PT-2026-64047

Summary PostCSS's PreviousMap parses the / sourceMappingURL=PATH / comment from any CSS string passed to process and dereferences PATH against the local filesystem with no scheme, allowlist, or traversal check. An attacker who controls the CSS input can cause the host process to read any file...

CVE-2026-49356

Babel is a compiler for writing next generation JavaScript. Prior to 8.0.0-rc.6 and 7.29.6, @babel/core affected by an arbitrary file read via a sourceMappingURL comment. Using @babel/core to compile maliciously crafted code can allow an attacker to read any source map from the system that is...

CVE-2026-49356

CVE-2026-49356 affects @babel/core (Babel) prior to versions 8.0.0-rc.6 and 7.29.6. The issue allows an arbitrary file read via a sourceMappingURL comment in the input code, enabling reading of source maps from the system running Babel when the attacker controls the input source code and knows th...

CVE-2026-49356 Babel: Arbitrary File Read via sourceMappingURL Comment in @babel/core

Babel is a compiler for writing next generation JavaScript. Prior to 8.0.0-rc.6 and 7.29.6, @babel/core affected by an arbitrary file read via a sourceMappingURL comment. Using @babel/core to compile maliciously crafted code can allow an attacker to read any source map from the system that is...