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CVE Record

CVE-2026-7263: DoS attack via DOMNode::C14N()

In PHP versions 8.4.* before 8.4.21 and 8.5.* before 8.5.6, DOMNode::C14N() method may process the XML data incorrectly, causing a circular linked list in the data structure representing the XML document. This may cause subsequent processing of the XML document to enter infinite loop, causing denial of service in the processing application.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in PHP's DOM XML handling can make an application hang when DOMNode::C14N() processes certain XML data. The result is denial of service, not data theft or code execution. Business impact depends on whether internet-facing PHP services canonicalize XML from users or partners.

Executive priority

Prioritize patching internet-facing or partner-facing PHP XML services. This is availability-focused, but the unauthenticated network CVSS profile makes outage risk credible where vulnerable XML canonicalization is reachable.

Technical view

PHP 8.4.* before 8.4.21 and 8.5.* before 8.5.6 can incorrectly process XML in DOMNode::C14N(), creating a circular linked list in the document structure. Later processing can enter an infinite loop. The CVSS vector is network-accessible, low complexity, unauthenticated, no user interaction, availability-only impact.

Likely exposure

Exposure is most likely in PHP applications using the DOM extension to canonicalize XML, especially services accepting untrusted XML. The provided sources identify PHP 8.4.* and 8.5.* below the fixed releases; they do not identify other products or frameworks as affected.

Exploitation context

The bundle marks KEV as false, and no provided source states active exploitation. The CVSS vector indicates remote unauthenticated triggering may be possible where an application exposes XML processing paths using DOMNode::C14N(). Do not assume exploit activity without new vendor, KEV, or incident evidence.

Researcher notes

The key unknown is application reachability: PHP is vulnerable only when affected versions process XML through DOMNode::C14N() and later handling loops. Sources do not provide exploit details, affected downstream products beyond PHP, or evidence of active exploitation.

Mitigation direction

  • Upgrade PHP 8.4 deployments to 8.4.21 or later.
  • Upgrade PHP 8.5 deployments to 8.5.6 or later.
  • Apply vendor-supported backported fixes for distribution-managed PHP packages.
  • Review vendor guidance before relying on configuration-only mitigations.
  • Reduce untrusted XML processing where canonicalization is not required.

Validation and detection

  • Inventory PHP runtime versions across production, staging, and container images.
  • Identify code paths calling DOMNode::C14N() or XML canonicalization wrappers.
  • Confirm whether those paths process external or unauthenticated XML input.
  • Verify patched package versions after updates or vendor errata application.
  • Monitor affected services for abnormal CPU saturation or request hangs.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-404: Exact CWE lookup

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cwe · low confidence lookup

CWE-835: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-7263 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP
6.3CVSS 4.0MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/AU:Y/RE:M/U:Amber——php

Vulnerability scoring details

Base CVSS 4.0 score

6.3Medium
CVSS 4.0 vector shape for CVE-2026-7263Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/AU:Y/RE:M/U:Amber

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPphp: denial of service via DOMNode::C14N()
other:Red Hat severity ratingcvssV3_1
  • 2026-05-10T06:00:59.933Z: Reported to Red Hat.
  • 2026-05-10T04:43:04.483Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
PHP GroupPHPdom, 8.4.*, 8.5.*unaffected
Weakness

CWE details

CWE-404CWE-835

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.