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: 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

CVE-2026-45623 affects PostCSS ≤ 8.5.11. The bug lives in the PreviousMap logic used during CSS processing: the sourceMappingURL comment is parsed without any scheme, allowlist, or traversal checks, and the attacker-controlled path is dereferenced to read files readable by the Node process. This ...

GHSA-R28C-9Q8G-F849 PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure

Vulnerability Details File: lib/previous-map.js Line: 87-98 loadFile, 129-144 loadMap Root Cause PostCSS auto-detects a / sourceMappingURL=... / comment inside the CSS text it is asked to parse and, unless the caller explicitly passes map: false, attempts to load that path from disk as a "previou...

CVE-2026-45623

creationtimestamp| type| source ---|---|--- 2026-07-23 16:35:02+00:00| published-proof-of-concept| https://github.com/postcss/postcss/security/advisories/GHSA-6g55-p6wh-862q 2026-08-03 18:28:13+00:00| seen| https://bsky.app/profile/cve.skyfleet.blue/post/gp5oyt6frvyqh 2026-08-03 18:31:17+00:00|...

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...

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

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...

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...

GHSA-6G55-P6WH-862Q PostCSS: Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments

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...

PT-2026-64149

Name of the Vulnerable Software and Affected Versions PostCSS versions 8.5.11 and earlier Description PostCSS processes CSS files by transforming them into an Abstract Syntax Tree. The PreviousMap component parses / sourceMappingURL=PATH / comments from CSS strings passed to the process function...

MAL-2026-10687 Malicious code in selparsecss-selector (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector f4f8e230628f3622bf88bcd590f98f8065a99ea3e71ef1bf3c330439b7671e1f [email protected] is a name-confusion fork of postcss-selector-parser: package.json declares author 'Ai Pyramid' while the LICENSE-MIT, sour...

MAL-2026-10614 Malicious code in postcss-selector-minify (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector 92fec62079856815ded46ba283769d3d3e0d20e08b6196b8698e08e2df6677ee Package is published as postcss-selector-minify a word-order permutation of cssnano's widely used postcss-minify-selectors and registers itself to...

Malicious code in postcss-processor-utils (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector b0253c4f750443ba47f0ab61347fa85a1659b847190a85757575e904966636da On require, src/index.js loads src/token-loader.js, which reads data/design-tokens.json, XOR-decodes the base64 blobs under encrypted.chunks using a...

MAL-2026-10540 Malicious code in postcss-processor-utils (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector b0253c4f750443ba47f0ab61347fa85a1659b847190a85757575e904966636da On require, src/index.js loads src/token-loader.js, which reads data/design-tokens.json, XOR-decodes the base64 blobs under encrypted.chunks using a...

MAL-2026-10539 Malicious code in postcss-animatecss (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector adfcae16a606f0b7eccb6cd94c1d1d0b583b19021bb15d04161f3ca8855aba61 The exported PostCSS plugin factory in [email protected] contains an obfuscator.io-obfuscated payload that executes on every consumer build...

Malicious code in animated-css-kit (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector 2156080aac79f8a251ee10f328ba8df515372cd8db293d45655ff32d54f61257 The package presents itself as a PostCSS plugin for animate.css, but its main export src/plugin.js createPlugin synchronously triggers...

MAL-2026-10432 Malicious code in animated-css-kit (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector 2156080aac79f8a251ee10f328ba8df515372cd8db293d45655ff32d54f61257 The package presents itself as a PostCSS plugin for animate.css, but its main export src/plugin.js createPlugin synchronously triggers...

MAL-2026-6684 Malicious code in postcss-property-rollup (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector acb8d62cdeb6a2c19937f3d02aa6214a23114e4dbc38373e6107c8345c3f1f9f [email protected] was scanned with no a static rule matches and no behavioral findings. No exfiltration, install-time fetch-and-execute,...

Malicious code in postcss-property-rollup (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector acb8d62cdeb6a2c19937f3d02aa6214a23114e4dbc38373e6107c8345c3f1f9f [email protected] was scanned with no a static rule matches and no behavioral findings. No exfiltration, install-time fetch-and-execute,...

MAL-2026-6578 Malicious code in layerd-unit-codec-parser (npm)

--- -= Per source details. Do not edit below this line.=- Source: amazon-inspector ca65bb450fc2f4d4596fbcc2ddd81af358c2d02f94d965b18e532d8afa62ef5f The package presents itself as a CSS selector parser src/selector-parser.js re-exports postcss-selector-parser; keywords postcss/selector/parser/css,...