Skip to content

Conversation

@renovate
Copy link
Contributor

@renovate renovate bot commented Jan 15, 2026

This PR contains the following updates:

Package Change Age Confidence
diff ^7.0.0^8.0.0 age confidence

GitHub Vulnerability Alerts

GHSA-73rr-hh4g-fpgx

Impact

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 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.

Patches

All vulnerabilities described are fixed in v8.0.3.

Workarounds

If using a version of jsdiff earlier than v8.0.3, do not attempt to parse patches that contain any of these characters: \r, \u2028, or \u2029.

References

PR that fixed the bug: https://github.com/kpdecker/jsdiff/pull/649


Release Notes

kpdecker/jsdiff (diff)

v8.0.3

Compare Source

  • #​631 - fix support for using an Intl.Segmenter with diffWords. This has been almost completely broken since the feature was added in v6.0.0, since it would outright crash on any text that featured two consecutive newlines between a pair of words (a very common case).
  • #​635 - small tweaks to tokenization behaviour of diffWords when used without an Intl.Segmenter. Specifically, the soft hyphen (U+00AD) is no longer considered to be a word break, and the multiplication and division signs (× and ÷) are now treated as punctuation instead of as letters / word characters.
  • #​641 - the format of file headers in createPatch etc. patches can now be customised somewhat. It now takes a headerOptions option that can be used to disable the file headers entirely, or omit the Index: line and/or the underline. In particular, this was motivated by a request to make jsdiff patches compatible with react-diff-view, which they now are if produced with headerOptions: FILE_HEADERS_ONLY.
  • #​647 and #​649 - fix denial-of-service vulnerabilities in parsePatch whereby adversarial input could cause a memory-leaking infinite loop, typically crashing the calling process. Also fixed ReDOS vulnerabilities whereby adversarially-crafted patch headers could take cubic time to parse. Now, parsePatch should reliably take linear time. (Handling of headers that include the line break characters \r, \u2028, or \u2029 in non-trailing positions is also now more reasonable as side effect of the fix.)

v8.0.2

Compare Source

  • #​616 Restored compatibility of diffSentences with old Safari versions. This was broken in 8.0.0 by the introduction of a regex with a lookbehind assertion; these weren't supported in Safari prior to version 16.4.
  • #​612 Improved tree shakeability by marking the built CJS and ESM packages with sideEffects: false.

v8.0.1

Compare Source

  • #​610 Fixes types for diffJson which were broken by 8.0.0. The new bundled types in 8.0.0 only allowed diffJson to be passed string arguments, but it should've been possible to pass either strings or objects (and now is). Thanks to Josh Kelley for the fix.

v8.0.0

Compare Source

  • #​580 Multiple tweaks to diffSentences:
    • tokenization no longer takes quadratic time on pathological inputs (reported as a ReDOS vulnerability by Snyk); is now linear instead
    • the final sentence in the string is now handled the same by the tokenizer regardless of whether it has a trailing punctuation mark or not. (Previously, "foo. bar." tokenized to ["foo.", " ", "bar."] but "foo. bar" tokenized to ["foo.", " bar"] - i.e. whether the space between sentences was treated as a separate token depended upon whether the final sentence had trailing punctuation or not. This was arbitrary and surprising; it is no longer the case.)
    • in a string that starts with a sentence end, like "! hello.", the "!" is now treated as a separate sentence
    • the README now correctly documents the tokenization behaviour (it was wrong before)
  • #​581 - fixed some regex operations used for tokenization in diffWords taking O(n^2) time in pathological cases
  • #​595 - fixed a crash in patch creation functions when handling a single hunk consisting of a very large number (e.g. >130k) of lines. (This was caused by spreading indefinitely-large arrays to .push() using .apply or the spread operator and hitting the JS-implementation-specific limit on the maximum number of arguments to a function, as shown at https://stackoverflow.com/a/56809779/1709587; thus the exact threshold to hit the error will depend on the environment in which you were running JsDiff.)
  • #​596 - removed the merge function. Previously JsDiff included an undocumented function called merge that was meant to, in some sense, merge patches. It had at least a couple of serious bugs that could lead to it returning unambiguously wrong results, and it was difficult to simply "fix" because it was unclear precisely what it was meant to do. For now, the fix is to remove it entirely.
  • #​591 - JsDiff's source code has been rewritten in TypeScript. This change entails the following changes for end users:
    • the diff package on npm now includes its own TypeScript type definitions. Users who previously used the @types/diff npm package from DefinitelyTyped should remove that dependency when upgrading JsDiff to v8.

      Note that the transition from the DefinitelyTyped types to JsDiff's own type definitions includes multiple fixes and also removes many exported types previously used for options arguments to diffing and patch-generation functions. (There are now different exported options types for abortable calls - ones with a timeout or maxEditLength that may give a result of undefined - and non-abortable calls.) See the TypeScript section of the README for some usage tips.

    • The Diff object is now a class. Custom extensions of Diff, as described in the "Defining custom diffing behaviors" section of the README, can therefore now be done by writing a class CustomDiff extends Diff and overriding methods, instead of the old way based on prototype inheritance. (I think code that did things the old way should still work, though!)

    • diff/lib/index.es6.js and diff/lib/index.mjs no longer exist, and the ESM version of the library is no longer bundled into a single file.

    • The ignoreWhitespace option for diffWords is no longer included in the type declarations. The effect of passing ignoreWhitespace: true has always been to make diffWords just call diffWordsWithSpace instead, which was confusing, because that behaviour doesn't seem properly described as "ignoring" whitespace at all. The property remains available to non-TypeScript applications for the sake of backwards compatibility, but TypeScript applications will now see a type error if they try to pass ignoreWhitespace: true to diffWords and should change their code to call diffWordsWithSpace instead.

    • JsDiff no longer purports to support ES3 environments. (I'm pretty sure it never truly did, despite claiming to in its README, since even the 1.0.0 release used Array.map which was added in ES5.)

  • #​601 - diffJson's stringifyReplacer option behaves more like JSON.stringify's replacer argument now. In particular:
    • Each key/value pair now gets passed through the replacer once instead of twice
    • The key passed to the replacer when the top-level object is passed in as value is now "" (previously, was undefined), and the key passed with an array element is the array index as a string, like "0" or "1" (previously was whatever the key for the entire array was). Both the new behaviours match that of JSON.stringify.
  • #​602 - diffing functions now consistently return undefined when called in async mode (i.e. with a callback). Previously, there was an odd quirk where they would return true if the strings being diffed were equal and undefined otherwise.

Configuration

📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant