Medium severity · published Aug 1, 2026
CVE-2026-67353
guzzlehttp/guzzle before 7.15.1 Unbounded Cookie Denial of Service
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GU
guzzle · guzzle
before 7.15.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-67353
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-67353
vendor-advisory
https://github.com/guzzle/guzzle/security/advisories/GHSA-f283-ghqc-fg79
third-party-advisory
https://www.vulncheck.com/advisories/guzzlehttp-guzzle-before-unbounded-cookie-denial-of-service
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6.1
CVE-2026-59883
Guzzle: Cookie Disclosure and Injection via IP-Address Domains
5.9
CVE-2026-67354
guzzlehttp/guzzle before 7.15.1 URI Fragment Disclosure via Referer
5.9
CVE-2026-67355
guzzlehttp/guzzle before 7.15.1 Host-only Cookie Scope