CVE-2026-7259Network attack vector

Process crash via mismatched regex encoding validation

Published May 10, 2026 · Updated May 10, 2026

NULL pointer dereference in PHP mbstring allows attackers to crash a PHP process through a crafted multibyte regex encoding. php_mb_regex_set_mbctype() accepts an Oniguruma-supported encoding even when mbfl_name2encoding() returns NULL, which php_mb_check_encoding() later dereferences during mb_ereg_search_init(). Affected releases are PHP 8.2.0 through 8.2.30, 8.3.0 through 8.3.30, 8.4.0 through 8.4.20, and 8.5.0 through 8.5.5; an application must let user-controlled input select mb_regex_encoding() and then invoke an mbregex search API.

CVSS severity2.1
Low
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in PHP mbstring allows attackers to crash a PHP process through a crafted multibyte regex encoding. php_mb_regex_set_mbctype() accepts an Oniguruma-supported encoding even when mbfl_name2encoding() returns NULL, which php_mb_check_encoding() later dereferences during mb_ereg_search_init(). Affected releases are PHP 8.2.0 through 8.2.30, 8.3.0 through 8.3.30, 8.4.0 through 8.4.20, and 8.5.0 through 8.5.5; an application must let user-controlled input select mb_regex_encoding() and then invoke an mbregex search API.

The record

CVE
CVE-2026-7259
Published
May 10, 2026
Updated
May 10, 2026
Vendor
The PHP Group
Product
PHP
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 10, 2026CVE publishedPublication date reported by the CVE source.
  2. May 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.2.* <8.2.31
  2. Affected versionversion=8.3.* <8.3.31
  3. Affected versionversion=8.4.* <8.4.21
  4. Affected versionversion=8.5.* <8.5.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The PHP Group · PHPversion=8.2.* <8.2.31; version=8.3.* <8.3.31; version=8.4.* <8.4.21; version=8.5.* <8.5.6

Published CVSS scores

2.1PHP GroupCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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