Security readout for executives and security teams
Plain-English summary
This is a low-severity local denial-of-service issue in Ubuntu’s AccountsService packaging. A local user-controlled environment file could cause AccountsService to read without bounds and hang, reducing availability rather than exposing data or enabling system takeover.
Executive priority
Treat as routine patching unless shared Ubuntu systems allow untrusted local users. The business impact is service disruption, not data theft or direct remote compromise, based on the supplied sources.
Technical view
Ubuntu-specific AccountsService versions before 0.6.55-0ubuntu13.2 perform unbounded reads from user-controlled ~/.pam_environment. The CVSS vector is local, low complexity, low privileges, user interaction required, with availability impact only and no confidentiality or integrity impact.
Likely exposure
Exposure is mainly Ubuntu systems running the listed vulnerable AccountsService package versions. Risk is highest where untrusted or many local users can create or modify home-directory environment files. This is not described as a remote network vulnerability.
Exploitation context
The provided bundle does not show active exploitation. KEV is false, and the cited sources describe a local availability flaw, not a public remote exploit campaign or privilege escalation path.
Researcher notes
Do not generalize this to all upstream AccountsService deployments without checking distro-specific patches. The source frames this as an Ubuntu-specific modification involving unbounded reads of user-controlled PAM environment data and CWE-20 input validation weakness.
Mitigation direction
- Update Ubuntu AccountsService packages to a vendor-fixed version.
- Prioritize systems with untrusted local user access.
- Check Ubuntu security guidance for exact fixed package versions.
- Limit unnecessary local accounts on shared systems.
- Monitor for AccountsService hangs or repeated service failures.
Validation and detection
- Inventory Ubuntu hosts and AccountsService package versions.
- Compare installed versions against the affected versions listed in the CVE bundle.
- Review user home directories for suspicious ~/.pam_environment symlink anomalies.
- Check logs for AccountsService hangs, crashes, or repeated restarts.
- Confirm patched systems run fixed vendor packages.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-20: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-16127 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Low
- CVSS
- 2.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L1.31.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
2.8LowVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOSCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.