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CVE-2026-7258 PHP Group CVE debrief

CVE-2026-7258 is a denial-of-service issue in PHP’s handling of some input-processing functions, including urldecode(). On affected systems with default signed char behavior and optimized table-lookup ctype implementations, a negative array offset may be accessed, which can crash the process. The issue was published on 2026-05-10 and is rated CVSS 6.3 (Medium).

Vendor
PHP Group
Product
PHP
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-10
Original CVE updated
2026-07-24
Advisory published
2026-05-10
Advisory updated
2026-07-24

Who should care

Administrators and developers running PHP 8.2.* before 8.2.31, 8.3.* before 8.3.31, 8.4.* before 8.4.21, or 8.5.* before 8.5.6 should care, especially on systems with default signed char behavior and optimized ctype implementations such as NetBSD-like environments.

Technical summary

According to the NVD record and the linked PHP security advisory, some PHP functions pass signed char values into ctype routines such as isxdigit(). On platforms where char is signed by default and the ctype implementation uses a table lookup, this can lead to an out-of-bounds array access with a negative offset. The described impact is denial of service. NVD maps the weakness to CWE-125.

Defensive priority

Medium. Prioritize faster remediation if the affected PHP runtime is internet-facing, handles untrusted input, or runs on a platform configuration matching the vulnerable conditions described in the advisory.

Recommended defensive actions

  • Upgrade PHP to a fixed release: 8.2.31, 8.3.31, 8.4.21, or 8.5.6, depending on your branch.
  • Inventory deployed PHP versions and identify any systems running the affected ranges.
  • Check whether your runtime platform uses default signed char behavior and an optimized table-lookup ctype implementation.
  • Review the linked PHP security advisory and vendor release notes for patch availability and deployment guidance.
  • After upgrading, validate application stability and monitor for unexpected PHP crashes or process restarts.

Evidence notes

This debrief is based only on the supplied NVD record and its official PHP advisory reference. The CVE was published and modified on 2026-05-10T05:16:11.360Z. The source description identifies the affected PHP version ranges and the signed-char/ctype condition that can trigger denial of service; no additional impact claims are assumed beyond that text.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-7258 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-7258

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-7258 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-7258

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.