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CVE-2022-31129 High

Moment.js vulnerable to Inefficient Regular Expression Complexity

### Impact * using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs * noticeable slowdown is observed with inputs above 10k characters * users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks ### Patches The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. ### Workarounds In general, given the proliferation of ReDoS attacks, it makes sense to limit the length of the user input to something sane, like 200 characters or less. I haven't seen legitimate cases of date-time strings longer than that, so all moment users who do pass a user-originating string to constructor are encouraged to apply such a rudimentary filter, that would help with this but also most future ReDoS vulnerabilities. ### References There is an excellent writeup of the issue here: https://github.com/moment/moment/pull/6015#issuecomment-1152961973= ### Details The issue is rooted in the code that removes legacy comments (stuff inside parenthesis) from strings during rfc2822 parsing. `moment("(".repeat(500000))` will take a few minutes to process, which is unacceptable.

Exploit probability 4.9%
Published July 6, 2022
Required by Not available
Last source change July 14, 2026

02 / AFFECTED SOFTWARE

Affected packages

NuGet Moment.js

26 explicit affected versions

npm moment
Unknown Unknown

25 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities GHSA-wc69-rhjr-hc9g

### Impact * using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs * noticeable slowdown is observed with inputs above 10k characters * users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks ### Patches The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. ### Workarounds In general, given the proliferation of ReDoS attacks, it makes sense to limit the length of the user input to something sane, like 200 characters or less. I haven't seen legitimate cases of date-time strings longer than that, so all moment users who do pass a user-originating string to constructor are encouraged to apply such a rudimentary filter, that would help with this but also most future ReDoS vulnerabilities. ### References There is an excellent writeup of the issue here: https://github.com/moment/moment/pull/6015#issuecomment-1152961973= ### Details The issue is rooted in the code that removes legacy comments (stuff inside parenthesis) from strings during rfc2822 parsing. `moment("(".repeat(500000))` will take a few minutes to process, which is unacceptable.

View original source
Open Source Vulnerabilities CVE-2022-31129

moment is a JavaScript date library for parsing, validating, manipulating, and formatting dates. Affected versions of moment were found to use an inefficient parsing algorithm. Specifically using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs. Users may notice a noticeable slowdown is observed with inputs above 10k characters. Users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks. The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. Users are advised to upgrade. Users unable to upgrade should consider limiting date lengths accepted from user input.

View original source

05 / REFERENCES

Further evidence