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Fencer Vulns
low 2.8

CVE-2020-16127 json

accountsservice .pam_environment infinite loop

published 2020-11-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-8093

cvss
2.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

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.

Patch / fix

  • Freedesktop accountsservice 0.6.35-0ubuntu7.3+esm2, 0.6.40-2ubuntu11.6, 0.6.45-1ubuntu1.3, 0.6.55-0ubuntu12~20.04.4, 0.6.55-0ubuntu13.2
  • accountsservice Ubuntu 20.04 LTS 0.6.55-0ubuntu12~20.04.4

ubuntu advisories UBUNTU-CVE-2020-16127

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • securitylab.github.com https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 2.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Freedesktop accountsservice

Classification

Weakness
  • CWE-20 Improper Input Validation
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.