REDHAT-BUG-2431930: High severity npm/jsdiff vulnerability
jsdiff is a JavaScript text differencing implementation. Prior to versions 8.0.3, 5.2.2, and 4.0.4, attempting to parse a patch whose filename headers contain the line break characters \r, \u2028, or \u2029 can cause the parsePatch method to enter an infinite loop. It then consumes memory without limit until the process crashes due to running out of memory. Applications are therefore likely to be vulnerable to a denial-of-service attack if they call parsePatch with a user-provided patch as input. A large payload is not needed to trigger the vulnerability, so size limits on user input do not provide any protection. Furthermore, some applications may be vulnerable even when calling parsePatch on a patch generated by the application itself if the user is nonetheless able to control the filename headers (e.g. by directly providing the filenames of the files to be diffed). The applyPatch method is similarly affected if (and only if) called with a string representation of a patch as an argument, since under the hood it parses that string using parsePatch. Other methods of the library are unaffected. Finally, a second and lesser interdependent bug - a ReDOS - also exhibits when those same line break characters are present in a patch's patch header (also known as its "leading garbage"). A maliciously-crafted patch header of length n can take parsePatch O(n³) time to parse. Versions 8.0.3, 5.2.2, and 4.0.4 contain a fix. As a workaround, do not attempt to parse patches that contain any of these characters: \r, \u2028, or \u2029.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
jsdiffto a version that resolves this vulnerability.Fixed in 8.0.3 - Upgrade
Upgrade
jsdiffto a version that resolves this vulnerability.Fixed in 5.2.2 - Upgrade
Upgrade
jsdiffto a version that resolves this vulnerability.Fixed in 4.0.4 - Configuration
As a workaround, do not attempt to parse patches that contain any of these characters in the patch filename headers: \r, \u2028, \u2029. This mitigates the DoS/infinite loop behavior when parsePatch receives user-provided patch input.
jsdiff parsePatch input patch filename headers = reject any patches whose filename headers contain line break characters \r, \u2028, or \u2029
Event History
Frequently Asked Questions
What is the severity of REDHAT-BUG-2431930?
The severity of REDHAT-BUG-2431930 is classified as high with a score of 7.
How do I fix REDHAT-BUG-2431930?
To fix REDHAT-BUG-2431930, update to jsdiff versions 8.0.3, 5.2.2, or 4.0.4 or later.
What causes the issue in REDHAT-BUG-2431930?
The issue in REDHAT-BUG-2431930 is caused by the `parsePatch` method entering an infinite loop when parsing a patch with specific line break characters in the filename headers.
What software is affected by REDHAT-BUG-2431930?
The affected software by REDHAT-BUG-2431930 is the npm package jsdiff.
When was REDHAT-BUG-2431930 published?
REDHAT-BUG-2431930 was published on January 22, 2026.