CVE-2026-59883: Guzzle is an extensible PHP HTTP client

Q: How do I fix CVE-2026-59883?

guzzle: upgrade to 7.12.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-59883 being exploited?

CVE-2026-59883 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-59883 affect?

CVE-2026-59883 affects guzzle. Severity is medium (CVSS 4.7). 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 matc

Q: How urgent is CVE-2026-59883?

Priority 18/100. No elevated risk signals yet.

Routine

MEDIUM 4.7UPGRADE

CVE-2026-59883 is a medium-severity flaw (CVSS 4.7) affecting guzzle. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.7 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-346, CWE-384
Published	2026-07-08
Last modified	2026-07-13

Publisher (CNA): GitHub, Inc. · Vendor: guzzlephp

Last updated 2026-07-13 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-08 17:17 UTCPublished CVE record published
2026-07-13 14:01 UTCUpdated Record last modified

guzzlephp guzzle UPGRADE

Affected: < 7.12.3

Fixed in: 7.12.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy guzzle || rpm -q guzzle || guzzle --version

2. UPGRADE to 7.12.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade guzzle

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade guzzle

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-59883?

guzzle: upgrade to 7.12.3. Exact commands for each OS are on this page.

Is CVE-2026-59883 being exploited?

CVE-2026-59883 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-59883 affect?

CVE-2026-59883 affects guzzle. Severity is medium (CVSS 4.7). 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 matc

How urgent is CVE-2026-59883?

Priority 18/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

Related CVEs

CVE-2026-55767 MEDIUM 5.8 UPGRADE Guzzle is an extensible PHP HTTP client
CVE-2026-55568 MEDIUM 5.9 UPGRADE Guzzle is an extensible PHP HTTP client

References

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