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

> Attackers can disclose or inject cookies across different IP-address hosts due to improper domain matching in the Guzzle PHP HTTP client library.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 8 Jul 2026
- **Updated:** 9 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-59883, GHSA-g446-98w2-8p5w, MINI-6mxm-xrwg-7f3r, MINI-9fhr-8prm-x7q6, MINI-cq5g-g8p8-r42h, MINI-f7pp-9rv3-pwv2, MINI-hwfg-wgwx-c7mh, MINI-jvx7-6v4w-479c, MINI-p4fg-8qmj-9gh3, MINI-wm8p-794c-6v6f, MINI-xxpr-pxvg-7j6v, UBUNTU-CVE-2026-59883

## What is CVE-2026-59883?

CVE-2026-59883 is a medium-severity vulnerability in guzzle, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-384 (Session Fixation), CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2026-59883?

2 open source packages ship an affected version, including guzzlehttp/guzzle. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `guzzlehttp/guzzle` | Packagist | All versions | 7.12.3 |
| `guzzlehttp/guzzle` | Packagist | All versions | 7.12.3 |

Products: Guzzlephp Guzzle.

## How do I fix CVE-2026-59883?

Upgrade guzzlehttp/guzzle to 7.12.3 or later.

## Is CVE-2026-59883 being exploited?

There is no known exploitation of CVE-2026-59883 in the wild and no public exploit code.

## Other vulnerabilities in guzzle

- [CVE-2026-55568](https://insights.sbomify.com/CVE-2026-55568/): Guzzle: Silent HTTPS-Proxy Downgrade to Cleartext (medium 5.9)
- [CVE-2026-55767](https://insights.sbomify.com/CVE-2026-55767/): Guzzle: Dot-Only Cookie Domains Match All Hosts in guzzlehttp/guzzle (medium 5.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59883 and fix it if it is affected.

What it is: CVE-2026-59883 is a medium-severity vulnerability in guzzle, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-59883 in the wild and no public exploit code.

Affected packages and fixed versions:
- guzzlehttp/guzzle (Packagist): affected all versions; fixed in 7.12.3
- guzzlehttp/guzzle (Packagist): affected all versions; fixed in 7.12.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-59883/ (Markdown: https://insights.sbomify.com/CVE-2026-59883/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59883
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59883
- OSV: https://osv.dev/vulnerability/CVE-2026-59883

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59883/
Summaries are generated and may contain mistakes; the official description above is the record.