CVE-2026-67353: Guzzle

Medium severity, CVSS 5.3. EPSS: 0.4% chance of exploitation in the next 30 days.

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 products

• Guzzle Guzzle: before 7.15.1 (fixed in 7.15.1)

Published 2026-08-01. Last modified 2026-10-08.