CVE-2026-67353: guzzlehttp/guzzle before 7.15.1 Unbounded Cookie Denial of Service
guzzlehttp/guzzle versions before 7.15.1 contain a denial of service vulnerability in the CookieJar that accepts unlimited Set-Cookie header fields with no size restrictions. Attackers can return many large cookies from a malicious server, causing Guzzle to store excessive data in memory and generate oversized Cookie headers that fail in handlers or destination servers.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
guzzlehttp/guzzleto a version that resolves this vulnerability.Fixed in 7.15.1