CVE-2026-55767
MEDIUMCVSS v3.1: 5.8
Source data as of:
At a glance
- Severity
- MEDIUM
- CVSS
- 5.8 v3.1 · NVD
- EPSS
- EPSS not provided by FIRST.org for this CVE
- CISA KEV
- No
- Attack conditions (CVSS vector)
- NetworkNo privilegesNo user interaction · Source: NVD Vector
- Published
- 2026-06-23 · Modified: 2026-06-23
- References
- Jump to references (1)
CVSS / EPSS / KEV
Source — CVSS: NVD · EPSS: FIRST.org · KEV: CISA. Data & Sources
Description
Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, CookieJar incorrectly accepts cookies with a dot-only Domain attribute and whitespace-padded variants. SetCookie::matchesDomain() removes leading dots from the cookie domain, normalizing dot-only values to the empty string; SetCookie::validate() only rejected a strictly empty domain, so these cookies could be stored and the empty normalized domain was treated as matching any request host. An attacker-controlled origin that an application requests with a shared cookie jar can therefore set a cookie that Guzzle later sends to unrelated hosts using the same jar. This may allow cookie injection or session fixation against downstream services, depending on how those services interpret the injected cookie. This vulnerability is fixed in 7.12.1.
References
Reference URLs as listed by NVD, grouped by a mechanical match on the link's host/pattern. Labels describe the link type only.