high7.5
CVE-2026-86250
h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() funct…
Impact
h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() functions. Attackers can send a crafted cookie header with an extremely large chunk count to trigger an O(n²) cleanup loop that hangs the server process.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | h3 | >= 2.0.0-beta.4, < 2.0.1-rc.18 | 2.0.1-rc.18 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-q5pr-72pq-83v3
- https://github.com/h3js/h3/security/advisories/GHSA-q5pr-72pq-83v3
- https://github.com/h3js/h3/commit/399257cb406fbeda313d88c1e288a15124fc82af
- https://github.com/h3js/h3/releases/tag/v2.0.1-rc.18
- https://nvd.nist.gov/vuln/detail/CVE-2026-86250
- https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-denial-of-service-via-unbounded-chunked-cookie