CVE-2026-7263Public exploitNetwork attack vector

Application crash or hang via C14N list corruption

Published May 10, 2026 · Updated May 10, 2026

Denial of service in PHP 8.4.0 through 8.4.20 and 8.5.0 through 8.5.5 allows remote attackers to crash or hang applications via crafted XML. In ext/dom/node.c, DOMNode::C14N() assigns attr->next to attr->prev instead of updating attr->prev->next when removing an xmlns attribute, corrupting the doubly linked list into a cycle. The application must pass attacker-controlled XML with an empty xmlns attribute to C14N(); later iteration or cleanup can loop indefinitely, exhaust resources, or segfault.

CVSS severity6.3
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in PHP 8.4.0 through 8.4.20 and 8.5.0 through 8.5.5 allows remote attackers to crash or hang applications via crafted XML. In ext/dom/node.c, DOMNode::C14N() assigns attr->next to attr->prev instead of updating attr->prev->next when removing an xmlns attribute, corrupting the doubly linked list into a cycle. The application must pass attacker-controlled XML with an empty xmlns attribute to C14N(); later iteration or cleanup can loop indefinitely, exhaust resources, or segfault.

The record

CVE
CVE-2026-7263
Published
May 10, 2026
Updated
May 10, 2026
Vendor
The PHP Group
Product
PHP
Classifications
CWE-835, CWE-404, 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=8.4.* <8.4.21
  2. Affected versionversion=8.5.* <8.5.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The PHP Group · PHPversion=8.4.* <8.4.21; version=8.5.* <8.5.6

Published CVSS scores

6.3The PHP GroupCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
CWE-404Improper Resource Shutdown or Release
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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