CVE-2026-84997: react/http: A malformed HTTP chunked body can lead to a denial-of-service and peg the CPU

high Affects react/http. Feed 2026.10.29.1, updated 2026-10-28; published 2026-09-17.

react/http: A malformed HTTP chunked body can lead to a denial-of-service and peg the CPU

Package: react/http Composer
Affected versions: >=0.6.0 and <1.11.1
Fixed in: 1.11.1
Severity: high CVSS 7.5
Exploitation: not on CISA KEV · EPSS 1% (51.2th percentile)
Published: 2026-09-17
Source: osv.dev

References

Am I affected?

Find out in one command. phpwarden checks your composer.lock against this advisory and 20,000+ others, ranked by real-world exploitation (CISA KEV + EPSS). Free, offline, open data.

# one-time install
pip install phpwarden

# then
phpwarden deps composer.lock

Or keep it checked automatically: GitHub Action · pre-commit hook · GitLab CI · Laravel artisan command

Install docs How findings are ranked

Related advisories

CVE-2022-36032 medium ReactPHP's HTTP server parses encoded cookie names so malicious `__Host-` and `__Secure-` same package: react/http
CVE-2023-26044 medium ReactPHP's HTTP server continues parsing unused multipart parts after reaching input field same package: react/http
CVE-2026-104827 high react/http: Unbounded HTTP Client Response Header Buffering Leads to Memory Exhaustion DoS same package: react/http
GHSA-g4f2-2pf3-2pwj unknown Unbounded HTTP Client Response Header Buffering Leads to Memory Exhaustion DoS in react/ht same package: react/http
CVE-2023-45363 high MediaWiki Denial of Service vulnerability same weakness: CWE-835
CVE-2026-43871 high Apache Thrift Python, Go, PHP and Java bindings have an Infinite Loop same weakness: CWE-835