--- title: "CVE-2025-6491\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2025-6491?format=md keywords: index, follow --- # CVE-2025-6491 Publication date 13 July 2025 Last updated 26 August 2025 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **5.9 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2025-6491?format=md#impact-score) Toggle side navigation ## Description In PHP versions:8.1.\* before 8.1.33, 8.2.\* before 8.2.29, 8.3.\* before 8.3.23, 8.4.\* before 8.4.10 when parsing XML data in SOAP extensions, overly large (>2Gb) XML namespace prefix may lead to null pointer dereference. This may lead to crashes and affect the availability of the target server. ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | php5 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 14.04 LTS trusty | Needs evaluation | | php7.0 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 16.04 LTS xenial | Fixed 7.0.33-0ubuntu0.16.04.16+esm16 Ubuntu Pro | | php7.2 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 18.04 LTS bionic | Fixed 7.2.24-0ubuntu0.18.04.17+esm9 Ubuntu Pro | | php7.4 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 20.04 LTS focal | Fixed 7.4.3-4ubuntu2.29+esm1 Ubuntu Pro | | php8.1 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Fixed 8.1.2-1ubuntu2.22 | | php8.3 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Ignored end of life, was needs-triage | | 24.04 LTS noble | Fixed 8.3.6-0ubuntu0.24.04.5 | | 22.04 LTS jammy | Not in release | | php8.4 | 26.04 LTS resolute | Not in release | | 25.10 questing | Fixed 8.4.11-1ubuntu1 | | 25.04 plucky | Fixed 8.4.5-1ubuntu1.1 | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) * [Patch details](https://ubuntu.com/security/CVE-2025-6491?format=md#patch-details) ### Get expanded security coverage with Ubuntu Pro Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use. [Get Ubuntu Pro](https://ubuntu.com/pro) [30-day free trial](https://ubuntu.com/pro/free-trial) ### Patch details For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) | Package | Patch details | | --- | --- | | php8.1 | * Upstream: [9cb3d8d](https://github.com/php/php-src/commit/9cb3d8d200f0c822b17bda35a2a67a97b039d3e1) | | php8.4 | * Upstream: [0298837](https://github.com/php/php-src/commit/0298837252fda06e0f86be3dfe91f166f45e85d4) | ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 5.9 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Network | | Attack complexity | High | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | None | | Integrity impact | None | | Availability impact | High | * Scores | Parameter | Value | | --- | --- | | Base score | 5.9 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-6491) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2025-6491) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2025-6491) * [Debian](https://security-tracker.debian.org/tracker/CVE-2025-6491) ### Related Ubuntu Security Notices (USN) + [USN-7648-1](https://usn.ubuntu.com/USN-7648-1) + PHP vulnerabilities + 17 July 2025 + [USN-7648-2](https://usn.ubuntu.com/USN-7648-2) + PHP vulnerabilities + 21 August 2025 ### Other references * *