---
id: CVE-2023-6779
title: 'Glibc: off-by-one heap-based buffer overflow in __vsyslog_internal()'
summary: >-
  An off-by-one 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 these functions are called with a
  message big…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2025-06-13T16:08:30.700931Z'
published: '2024-01-31'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T22:15:19.456Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-6779'
references:
  - url: >-
      http://packetstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.html
  - url: 'http://seclists.org/fulldisclosure/2024/Feb/3'
  - url: 'https://access.redhat.com/security/cve/CVE-2023-6779'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2254395'
    label: RHBZ#2254395
  - 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-20240223-0006/'
tags:
  - cve.org
epss: 0.03153
epssPercentile: 0.8771
ingestedAt: '2026-10-15T04:46:37.153Z'
---

## Overview

An off-by-one 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 these functions are called with a message bigger than INT_MAX bytes, leading to an incorrect calculation of the buffer size to store the message, resulting in an application crash. This issue affects glibc 2.37 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.