---
id: "CVE-2026-104715"
kind: "vulnerability"
aliases: ["CVE-2026-104715"]
title: "cifs-utils: local user escalates to root through injected mount options"
severity: "high"
cvss: 7.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "cifs-utils", "fixed": ["7.9"], "affected": ">= 4.2, <= 7.8", "ecosystem": "linux"}]
ecosystems: []
tags: ["cifs", "cifs-utils", "infrastructure", "linux", "local-privilege-escalation", "pam_mount", "self-hosted", "smb"]
not_affected_if: ["credentials-file-not-user-writable", "default-config", "no-cifs-mounts"]
published_at: "2026-10-16T07:17:08+00:00"
first_seen_at: "2026-10-23T21:57:12+00:00"
updated_at: "2026-10-25T03:49:04+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-104715", "first_seen_at": "2026-10-23T21:57:12+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-25T03:49:04+00:00"}]
---

# cifs-utils: local user escalates to root through injected mount options

cifs-utils mishandles input from a user-controlled credentials file when a privileged service mounts a CIFS share. A local user can inject unauthorized mount options, bypass permission checks and run files with root privileges.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- linux:cifs-utils affected >= 4.2, <= 7.8 fixed 7.9

## How to check

- Run mount.cifs -V (or your package manager's cifs-utils version). Versions 4.2 to 7.8 are affected unless your distro has backported the fix; check the package changelog for CVE-2026-104715.
- Look for privileged mounts that read a credentials= file from a user-writable location (pam_mount, automount, systemd units, fstab with user-owned files): grep -r credentials /etc/fstab /etc/security/pam_mount.conf.xml

## Fix

Upgrade to cifs-utils 7.9 or a distro backport: Ubuntu 26.10 2:7.4-1ubuntu3.1, 26.04 2:7.4-1ubuntu0.26.04.4, 24.04 2:7.0-2ubuntu0.6, 22.04 2:6.14-1ubuntu0.7; Debian trixie 2:7.4-1+deb13u2 (bookworm still vulnerable at last check), sid 2:7.9-1; Fedora 43 7.7-2; SUSE SU-2026:4819-1. Until patched, make credentials files root-owned and not user-writable.

## Timeline

- 2026-10-23T21:57:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-104715
- 2026-10-25T03:49:04+00:00 analyst — Upstream oss-security post (cifs-utils maintainers): affected 4.2-7.8, fixed in 7.9; distros backport (Ubuntu, Debian, SUSE, Fedora 7.7-2). Red Hat: Important, only non-default setups (e.g. pam_mount with credentials file in user-writable dir). Patches reject option delimiters in username/domain (Ubuntu changelog). No exploitation or PoC found; did not search social.

## Documents

- [advisory] oss-security: CVE-2026-104715 cifs-utils 4.2-7.8 mount-option injection (upstream, fixed in 7.9) http://www.openwall.com/lists/oss-security/2026/10/16/35
- [advisory] Red Hat CVE-2026-104715 https://access.redhat.com/security/cve/cve-2026-104715
- [fix] Ubuntu CVE-2026-104715 https://ubuntu.com/security/CVE-2026-104715
- [fix] Debian tracker CVE-2026-104715 https://security-tracker.debian.org/tracker/CVE-2026-104715

## From the sources

A flaw was found in cifs-utils. This flaw allows an unprivileged local user to achieve privilege escalation. When a privileged service mounts a Common Internet File System (CIFS) share using a user-controlled credentials file, input values are not properly sanitized before being assembled into mount options. A local attacker can exploit this vulnerability to inject unauthorized mount options, allowing them to bypass permission checks and execute files with administrative (root) privileges.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_