CVE-2020-25697

Local privilege escalation via unauthenticated X11 server impersonation

Published May 26, 2021 · Updated Aug 4, 2024

Missing X11 server authentication in X.Org Server allows local users to take control of privileged X applications through impersonation. X11 clients connect to the display socket without authenticating the server, allowing a forged endpoint to supply trusted protocol responses. Exploitation requires the legitimate server socket to disappear and an attacker-controlled socket to win the connection race; failure can instead prevent clients or the server from starting.

CVSS severity7.0
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing X11 server authentication in X.Org Server allows local users to take control of privileged X applications through impersonation. X11 clients connect to the display socket without authenticating the server, allowing a forged endpoint to supply trusted protocol responses. Exploitation requires the legitimate server socket to disappear and an attacker-controlled socket to win the connection race; failure can instead prevent clients or the server from starting.

The record

CVE
CVE-2020-25697
Published
May 26, 2021
Updated
Aug 4, 2024
Vendor
X.Org
Product
X.Org Server
Classifications
CWE-306, T1557
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=All

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

X.Org · X.Org Serverversion=All

Published CVSS scores

7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.4NIST NVDAV:L/AC:M/Au:N/C:P/I:P/A:P

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-306Missing Authentication for Critical Function
T1557Adversary-in-the-Middle

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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