CVE-2026-25704

Local privileged file access via retained root groups

Published Mar 30, 2026 · Updated Mar 30, 2026

Incomplete privilege dropping in Pop!_OS cosmic-greeter before 1.0.9 allows local users to redirect privileged file access or interrupt the daemon. The root-running cosmic-greeter-daemon changes only its effective user ID while GetUserData processes home-directory configuration, retaining root group credentials across separate file checks and opens. Direct calls require cosmic-greeter group membership; otherwise a local user must wait for an authorized call, while crafted links or special files can redirect parsing, hang the service, or exhaust memory.

CVSS severity5.8
Medium
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incomplete privilege dropping in Pop!_OS cosmic-greeter before 1.0.9 allows local users to redirect privileged file access or interrupt the daemon. The root-running cosmic-greeter-daemon changes only its effective user ID while GetUserData processes home-directory configuration, retaining root group credentials across separate file checks and opens. Direct calls require cosmic-greeter group membership; otherwise a local user must wait for an authorized call, while crafted links or special files can redirect parsing, hang the service, or exhaust memory.

The record

CVE
CVE-2026-25704
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
Pop!_OS
Product
cosmic-greeter
Classifications
CWE-367, CWE-271, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=? <https://github.com/pop-os/cosmic-greeter/pull/426

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Pop!_OS · cosmic-greeterversion=? <https://github.com/pop-os/cosmic-greeter/pull/426

Published CVSS scores

5.8SUSECVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-271Privilege Dropping / Lowering Errors
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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