CVE-2020-16127

accountsservice .pam_environment infinite loop

2.8 LowFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: Required

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.41%Down 1.4 points since Apr 14, 2021

What each source reports

CVE List Score used 2.8

accountsservice .pam_environment infinite loop

Record: CVE-2020-16127
CVSS 3.1: 2.8 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Weakness: CWE-20
Updated: 2026-11-02

EUVDEUVD-2020-8093 2.8

Record: EUVD-2020-8093
CVSS 3.1: 2.8 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Updated: 2026-11-03

GitHub AdvisoriesGHSA-vg2p-x98m-7mxr No score

An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among...

Record: GHSA-vg2p-x98m-7mxr
Weakness: CWE-835
Updated: 2026-11-02

NVD 2.8

Record: CVE-2020-16127
CVSS 3.1: 2.8 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 2.1 LowAV:L/AC:L/Au:N/C:N/I:N/A:P
Weakness: CWE-20, CWE-835
Updated: 2026-11-02

OSVUBUNTU-CVE-2020-16127 5.5

Record: UBUNTU-CVE-2020-16127
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1: 2.8 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Updated: 2026-11-02

OSVUSN-4616-1 No score

accountsservice vulnerabilities

Kevin Backhouse discovered that AccountsService incorrectly dropped privileges. A local user could possibly use this issue to cause AccountsService to crash or hang, resulting in a denial of service. (CVE-2020-16126)

Kevin Backhouse discovered that AccountsService incorrectly handled reading .pam_environment files. A local user could possibly use this issue to cause AccountsService to crash or hang, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS and Ubuntu 20.10. (CVE-2020-16127)

Matthias Gerstner discovered that AccountsService incorrectly handled certain path checks. A local attacker could possibly use this issue to read arbitrary files. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-14036)

Record: USN-4616-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`accountsservice` Ubuntu:20.04:LTS	before 0.6.55-0ubuntu12~20.04.4, plus listed versions 0.6.55-0ubuntu100.6.55-0ubuntu110.6.55-0ubuntu12~20.04.10.6.55-0ubuntu12~20.04.2	0.6.55-0ubuntu12~20.04.4
`accountsservice` Ubuntu:16.04:LTS	before 0.6.40-2ubuntu11.6, plus listed versions 0.6.40-2ubuntu50.6.40-2ubuntu60.6.40-2ubuntu70.6.40-2ubuntu80.6.40-2ubuntu9 Show 5 moreShow less 0.6.40-2ubuntu100.6.40-2ubuntu110.6.40-2ubuntu11.10.6.40-2ubuntu11.20.6.40-2ubuntu11.3	0.6.40-2ubuntu11.6
`accountsservice` Ubuntu:18.04:LTS	before 0.6.45-1ubuntu1.3, plus listed versions 0.6.42-0ubuntu30.6.42-0ubuntu40.6.45-1ubuntu1	0.6.45-1ubuntu1.3

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, products	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-16127 is a low vulnerability (CVSS 2.8) in Freedesktop Accountsservice, published November 3, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. Fixed in accountsservice 0.6.55-0ubuntu12~20.04.4.