What’s Vulnerable › Vulnerabilities

CVE-2020-16127: accountsservice .pam_environment infinite loop

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-11-11 · updated 2026-06-17
• Weakness: CWE-20

Description

An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.

Affected products

• Freedesktop accountsservice: before 0.6.55 — fixed in 0.6.55

How to fix

Upgrade to a fixed version: Freedesktop accountsservice 0.6.55. Check the vendor advisory for mitigations.

References

• https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS
• https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS

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