CVE-2026-67353

guzzlehttp/guzzle before 7.15.1 Unbounded Cookie Denial of Service

MEDIUM
5.3
CVSS Score
Published: August 1, 2026 at 12:22 PM UTC
Updated: October 8, 2026 at 04:17 PM UTC
2 products affected across 2 vendorsGuzzleGuzzle

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 7.15.1
Affected range stops below 7.15.1, so it looks safe — our inference, not a vendor statement
0 ≤ v < 7.15.10
Vendor states this is fixed in 7.15.1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-770

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