How severe is CVE-2026-59883?

CVE-2026-59883 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-59883 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-59883?

CVE-2026-59883 affects Guzzlephp Guzzle. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-59883?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-59883 published?

CVE-2026-59883 was published on 2026-07-08 and last updated on 2026-07-13.

CVE-2026-59883

CVE-2026-59883 is a medium-severity vulnerability in Guzzlephp Guzzle with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-346.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Affected product: Guzzlephp Guzzle
Published: 2026-07-08
Last modified: 2026-07-13

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.

Frequently asked questions

What is CVE-2026-59883?: 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.
How severe is CVE-2026-59883?: CVE-2026-59883 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-59883 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-59883?: CVE-2026-59883 affects Guzzlephp Guzzle. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-59883?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-59883 published?: CVE-2026-59883 was published on 2026-07-08 and last updated on 2026-07-13.

References

Affected products (1)

cpe:2.3:a:guzzlephp:guzzle:*:*:*:*:*:*:*:*

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