---
id: CVE-2026-12505
title: >-
  A flaw was found in the cifs-utils package where the cifs.upcall helper fails
  to securely drop its root privileges before looking up user information inside
  a user-controlled environment
summary: >-
  A flaw was found in the cifs-utils package where the cifs.upcall helper fails
  to securely drop its root privileges before looking up user information inside
  a user-controlled environment. A local, low privileged attacker can exploit
  this…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-250
  - CWE-250
published: '2026-06-18'
updated: '2026-07-15'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-12505'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:32990'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:39575'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:39576'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-12505'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2489805'
    label: secalert@redhat.com
  - url: >-
      https://git.samba.org/?p=cifs-utils.git;a=commit;h=972c5b5ff95e3e812bc8daa72d0383654ab0dba7
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:32990'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:39575'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:39576'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-12505'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2489805'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12505.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
epss: 0.00157
epssPercentile: 0.04084
ingestedAt: '2026-07-16T02:48:55.120Z'
---

## Overview

A flaw was found in the cifs-utils package where the cifs.upcall helper fails to securely drop its root privileges before looking up user information inside a user-controlled environment. A local, low privileged attacker can exploit this by using a crafted request_key payload to trick the root-owned helper into entering a custom environment (namespace) containing a malicious NSS module. This forces the system to load the attacker's controlled NSS Module and configuration, allowing them to execute arbitrary commands as the root user, elevating their privileges and fully compromising the system.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.