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CVE-2026-49356 Low

@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 path of the source map file that they want to read **Users that only compile trusted code are not impacted.** ## Patches The vulnerability has been fixed in `@babel/[email protected]` and `@babel/[email protected]`. ## Workarounds Callers can mitigate the issue without upgrading by setting [`inputSourceMap: false`](https://babeljs.io/docs/options#inputsourcemap) in their Babel options. Callers can also manually extract the `#sourceMappingURL` comment from the input source code, validate whether the source map that it links to is allowed to be read, and if it is pass an object to `inputSourceMap` (passing `false` when it's not). ## Credits Thanks Teodor-Cristian Radoi for reporting the vulnerability.

Exploit probability 0.1%
Published June 15, 2026
Required by Not available
Last source change July 15, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

841 explicit affected versions

npm @babel/core

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities 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 running Babel, if the attacker controls the input source code, can read the output source code, and knows the path of the source map file that they want to read. This vulnerability is fixed in 8.0.0-rc.6 and 7.29.6.

View original source
Open Source Vulnerabilities GHSA-4x5r-pxfx-6jf8

## 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 path of the source map file that they want to read **Users that only compile trusted code are not impacted.** ## Patches The vulnerability has been fixed in `@babel/[email protected]` and `@babel/[email protected]`. ## Workarounds Callers can mitigate the issue without upgrading by setting [`inputSourceMap: false`](https://babeljs.io/docs/options#inputsourcemap) in their Babel options. Callers can also manually extract the `#sourceMappingURL` comment from the input source code, validate whether the source map that it links to is allowed to be read, and if it is pass an object to `inputSourceMap` (passing `false` when it's not). ## Credits Thanks Teodor-Cristian Radoi for reporting the vulnerability.

View original source

05 / REFERENCES

Further evidence