---
id: CVE-2023-6246
title: 'Glibc: heap-based buffer overflow in __vsyslog_internal()'
summary: >-
  A heap-based buffer overflow was found in the __vsyslog_internal function of
  the glibc library. This function is called by the syslog and vsyslog
  functions. This issue occurs when the openlog function was not called, or
  called with the i…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-122
vendor: Red Hat
product: glibc
affected:
  - glibc
  - compat-glibc
  - glibc
  - compat-glibc
  - glibc
  - glibc
  - glibc
  - glibc (all versions)
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2024-02-09T05:00:28.307432Z'
exploitAvailable: true
published: '2024-01-31'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T22:15:16.680Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-6246'
references:
  - url: >-
      http://packetstormsecurity.com/files/176931/glibc-qsort-Out-Of-Bounds-Read-Write.html
  - url: >-
      http://packetstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.html
  - url: 'http://seclists.org/fulldisclosure/2024/Feb/3'
  - url: 'http://seclists.org/fulldisclosure/2024/Feb/5'
  - url: 'https://access.redhat.com/security/cve/CVE-2023-6246'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2249053'
    label: RHBZ#2249053
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/D2FIH77VHY3KCRROCXOT6L27WMZXSJ2G/
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MWQ6BZJ6CV5UAW4VZSKJ6TO4KIW2KWAQ/
  - url: 'https://security.gentoo.org/glsa/202402-01'
  - url: 'https://www.openwall.com/lists/oss-security/2024/01/30/6'
  - url: 'https://www.qualys.com/2024/01/30/cve-2023-6246/syslog.txt'
  - url: 'https://security.netapp.com/advisory/ntap-20240216-0007/'
tags:
  - cve.org
  - exploit-available
epss: 0.04794
epssPercentile: 0.91798
exploits:
  github: 2
  githubRepos:
    - 'https://github.com/elpe-pinillo/CVE-2023-6246'
    - 'https://github.com/SimoesCTT/CTT-Vsyslog-Vortex-CVE-2023-6246'
  checkedAt: '2026-10-15T04:47:12.159Z'
ingestedAt: '2026-10-15T04:46:37.153Z'
---

## Overview

A heap-based buffer overflow was found in the __vsyslog_internal function of the glibc library. This function is called by the syslog and vsyslog functions. This issue occurs when the openlog function was not called, or called with the ident argument set to NULL, and the program name (the basename of argv[0]) is bigger than 1024 bytes, resulting in an application crash or local privilege escalation. This issue affects glibc 2.36 and newer.

## Affected

- `glibc`
- `compat-glibc`
- `glibc`
- `compat-glibc`
- `glibc`
- `glibc`
- `glibc`
- `glibc (all versions)`

## Remediation

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