How severe is CVE-2026-59882?

CVE-2026-59882 has a CVSS 3.x base score of 4.2, 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-2026-59882 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-59882?

CVE-2026-59882 affects Guzzlephp Psr-7. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-59882?

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

When was CVE-2026-59882 published?

CVE-2026-59882 was published on 2026-07-08 and last updated on 2026-07-17.

CVE-2026-59882

CVE-2026-59882 is a medium-severity vulnerability in Guzzlephp Psr-7 with a CVSS 3.x base score of 4.2. 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-436.

Key facts

Severity: Medium (CVSS 3.x base score 4.2)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-436
Affected product: Guzzlephp Psr-7
Published: 2026-07-08
Last modified: 2026-07-17

Description

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.3, Uri::assertValidHost() does not reject URI host components containing authority delimiters, embedded ports, or malformed IPv6 brackets, allowing Uri::getHost() to disagree with the URI authority used for security or routing decisions. This issue is fixed in version 2.12.3.

Frequently asked questions

What is CVE-2026-59882?: guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.3, Uri::assertValidHost() does not reject URI host components containing authority delimiters, embedded ports, or malformed IPv6 brackets, allowing Uri::getHost() to disagree with the URI authority used for security or routing decisions. This issue is fixed in version 2.12.3.
How severe is CVE-2026-59882?: CVE-2026-59882 has a CVSS 3.x base score of 4.2, 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-2026-59882 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-59882?: CVE-2026-59882 affects Guzzlephp Psr-7. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-59882?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-59882 published?: CVE-2026-59882 was published on 2026-07-08 and last updated on 2026-07-17.

References

Affected products (1)

cpe:2.3:a:guzzlephp:psr-7:*:*:*:*:*:*:*:*

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