CVE-2026-25740

Local CAP_NET_RAW escalation via udhcpc wrapper

Published Feb 9, 2026 · Updated Feb 9, 2026

Privilege escalation in NixOS Nixpkgs 25.05 and earlier allows local users to run arbitrary commands with CAP_NET_RAW. The enabled programs.captive-browser module configures a system-wide udhcpc wrapper with CAP_NET_RAW for DNS discovery, allowing caller-selected script execution to inherit that capability. Exploitation requires a local account and programs.captive-browser.enable=true; resulting commands can perform raw-packet operations and spoof localhost traffic.

CVSS severity5.8
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in NixOS Nixpkgs 25.05 and earlier allows local users to run arbitrary commands with CAP_NET_RAW. The enabled programs.captive-browser module configures a system-wide udhcpc wrapper with CAP_NET_RAW for DNS discovery, allowing caller-selected script execution to inherit that capability. Exploitation requires a local account and programs.captive-browser.enable=true; resulting commands can perform raw-packet operations and spoof localhost traffic.

The record

CVE
CVE-2026-25740
Published
Feb 9, 2026
Updated
Feb 9, 2026
Vendor
NixOS
Product
Nixpkgs
Classifications
CWE-250, T1548
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 9, 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=<= 25.05

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

NixOS · Nixpkgsversion=<= 25.05

Published CVSS scores

5.8GitHub, Inc.CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-250Execution with Unnecessary Privileges
T1548Abuse Elevation Control Mechanism

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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