PHP up to 8.4.20/8.5.5 DOMNode::C14N denial of service

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3$0-$5k0.00

Summaryinfo

A vulnerability labeled as problematic has been found in PHP up to 8.4.20/8.5.5. Affected by this issue is the function DOMNode::C14N. The manipulation results in denial of service. This vulnerability is cataloged as CVE-2026-7263. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic has been found in PHP up to 8.4.20/8.5.5. Affected is the function DOMNode::C14N. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

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.

The weakness was shared by Nikita Sveshnikov as GHSA-4jhr-8w89-j733. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-7263 since 04/28/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/03/2026). The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 313734 (Fedora 44 : php (2026-c66eaae759)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 8.4.21 or 8.5.6 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (313734) and CERT Bund (WID-SEC-2026-1433). Once again VulDB remains the best source for vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Fedora Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure Linux
  • Open Source PHP
  • Zend ZendPHP
  • cPanel cPanel/WHM

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 313734
Nessus Name: Fedora 44 : php (2026-c66eaae759)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: PHP 8.4.21/8.5.6

Timelineinfo

04/28/2026 CVE reserved
05/10/2026 +12 days Advisory disclosed
05/10/2026 +0 days VulDB entry created
07/03/2026 +54 days VulDB entry last update

Sourcesinfo

Product: php.org

Advisory: GHSA-4jhr-8w89-j733
Researcher: Nikita Sveshnikov
Status: Confirmed

CVE: CVE-2026-7263 (🔒)
GCVE (CVE): GCVE-0-2026-7263
GCVE (VulDB): GCVE-100-362484
CERT Bund: WID-SEC-2026-1433 - PHP: Mehrere Schwachstellen

Entryinfo

Created: 05/10/2026 09:00
Updated: 07/03/2026 16:34
Changes: 05/10/2026 09:00 (72), 05/10/2026 10:42 (7), 05/11/2026 10:56 (2), 06/02/2026 02:18 (1), 06/04/2026 09:19 (1), 07/02/2026 19:25 (11), 07/03/2026 16:34 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!