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 ...

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...

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 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...

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...

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...

@babel/core: Arbitrary File Read via sourceMappingURL Comment

Impact Using @babel/core to compile maliciously crafted code can allow ab attacker to read any source map from the system that is running Babel, if these conditions are all true: - the attacker controls the input source code - the attacker can read the output source code - the attacker knows the...