---
id: CVE-2026-86805
title: >-
  A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader
  (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local
  attacker to escalate privileges
summary: >-
  A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader
  (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local
  attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for
  setuid/se…
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L'
cwe:
  - CWE-367
vendor: The GNU C Library
product: glibc
affected:
  - glibc >= 2.14 < 2.45
published: '2026-09-22'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T04:17:57.137'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86805'
references:
  - url: 'https://sourceware.org/bugzilla/show_bug.cgi?id=34360'
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: >-
      https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0022
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86805.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-86805'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2538209'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-86805'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86805'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-22T16:41:27.955407Z'
ingestedAt: '2026-09-22T16:06:00.471Z'
scores:
  nvd: 6.3
  vendor: 7
epss: 0.00124
epssPercentile: 0.01827
---

## Overview

A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for setuid/setgid (AT_SECURE) programs, glibc validates the lexically normalized search path against the trusted directories but then opens the raw, un-normalized path. On systems where the Linux fs.protected_hardlinks sysctl is disabled, a local attacker who hard-links such a program into an attacker-controlled directory and wins a race to replace an intermediate path component with a symbolic link can direct the loader outside the trusted directory, causing it to load an attacker-controlled shared object and execute arbitrary code with the elevated privileges of the program.

Exploitation requires an installed setuid or setgid binary whose DT_RPATH uses $ORIGIN followed by ".." traversal that normalizes into a trusted directory, and the ability to hard-link that binary and win the race by swapping a path component for a symbolic link. Major Linux-based OS distributions ship with fs.protected_hardlinks enabled by default and mitigate the vulnerability.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Hardened Images, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86805.json)