Multiple Denial of Service Vulnerabilities in polkit Affect Ubuntu Systems
Severity: Medium (Score: 57.8)
Sources: Linuxsecurity, Ubuntu
Summary
Two significant vulnerabilities have been identified in polkit, affecting multiple Ubuntu releases, including 25.10, 24.04 LTS, and 22.04 LTS. The first vulnerability (CVE-2025-7519), discovered in July 2025, allows remote attackers to exploit improperly handled nested XML elements, potentially causing a denial of service if an administrator installs a malicious policy file. The second vulnerability (CVE-2026-4897), reported by Pavel Kohout in March 2026, involves the polkit-agent-helper-1 utility mishandling long input, which could also lead to a denial of service by local attackers. Both vulnerabilities pose a risk of system crashes, impacting the stability of affected systems. Users are advised to update their systems to mitigate these vulnerabilities. A standard system update will address these issues across the affected Ubuntu versions. Key Points: • Two critical vulnerabilities in polkit affect multiple Ubuntu versions. • CVE-2025-7519 allows remote denial of service via malicious XML policy files. • CVE-2026-4897 enables local denial of service through mishandled input.
Key Entities
- Denial of Service (attack_type)
- CVE-2025-7519 (cve)
- CVE-2026-4897 (cve)
- T1499 - Endpoint Denial of Service (mitre_attack)
- Policykit-1 (platform)
- Polkit (platform)
- Polkitd (platform)
- Ubuntu (company)