Medium severity5.3NVD Advisory· Published Feb 16, 2021· Updated Jun 17, 2026
CVE-2021-21317
CVE-2021-21317
Description
uap-core in an open-source npm package which contains the core of BrowserScope's original user agent string parser. In uap-core before version 0.11.0, some regexes are vulnerable to regular expression denial of service (REDoS) due to overlapping capture groups. This allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to maliciously crafted long strings. This is fixed in version 0.11.0. Downstream packages such as uap-python, uap-ruby etc which depend upon uap-core follow different version schemes.
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Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
uap-corenpm | < 0.11.0 | 0.11.0 |
Affected products
3Patches
Vulnerability mechanics
References
5- github.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96cnvdPatchWEB
- github.com/advisories/GHSA-p4pj-mg4r-x6v4ghsaADVISORY
- github.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4nvdThird Party AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2021-21317ghsaADVISORY
- www.npmjs.com/package/uap-corenvdProductThird Party AdvisoryWEB
News mentions
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