Glibc: off-by-one heap-based buffer overflow in __vsyslog_internal()
Summary
| CVE | CVE-2023-6779 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2024-01-31 14:15:48 UTC |
| Updated | 2026-05-12 11:16:18 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.006540000 probability, percentile 0.710580000 (date 2026-05-12)
Problem Types: CWE-122 | CWE-787 | CWE-122 Heap-based Buffer Overflow
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | [email protected] | Secondary | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
| 3.1 | CNA | CVSS | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Fedoraproject | Fedora | 38 | All | All | All |
| Operating System | Fedoraproject | Fedora | 39 | All | All | All |
| Application | Gnu | Glibc | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Na | Glibc | unaffected 2.39 | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| CNA | Fedora | Fedora | Not specified | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | affected V3.1.5 * custom | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | affected V3.1.5 * custom | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | affected V3.1.5 * custom | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | affected V3.1.5 * custom | Not specified |
| ADP | Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP | affected V3.1.5 * custom | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| oss-security - CVE-2023-6246: Heap-based buffer overflow in the glibc's syslog() | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Exploit, Mailing List |
| [SECURITY] Fedora 38 Update: glibc-2.37-18.fc38 - package-announce - Fedora Mailing-Lists | af854a3a-2127-422b-91ae-364da2661108 | lists.fedoraproject.org | Mailing List |
| cert-portal.siemens.com/productcert/html/ssa-082556.html | 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e | cert-portal.siemens.com | |
| [SECURITY] Fedora 39 Update: glibc-2.38-16.fc39 - package-announce - Fedora Mailing-Lists | af854a3a-2127-422b-91ae-364da2661108 | lists.fedoraproject.org | Mailing List |
| glibc syslog() Heap-Based Buffer Overflow ≈ Packet Storm | af854a3a-2127-422b-91ae-364da2661108 | packetstormsecurity.com | Exploit, Third Party Advisory, VDB Entry |
| glibc: Multiple Vulnerabilities (GLSA 202402-01) — Gentoo security | af854a3a-2127-422b-91ae-364da2661108 | security.gentoo.org | Third Party Advisory |
| 2254395 – (CVE-2023-6779) CVE-2023-6779 glibc: off-by-one heap-based buffer overflow in __vsyslog_internal() | af854a3a-2127-422b-91ae-364da2661108 | bugzilla.redhat.com | Issue Tracking |
| cve-details | af854a3a-2127-422b-91ae-364da2661108 | access.redhat.com | Third Party Advisory |
| Full Disclosure: CVE-2023-6246: Heap-based buffer overflow in the glibc's syslog() | af854a3a-2127-422b-91ae-364da2661108 | seclists.org | Exploit, Mailing List, Third Party Advisory |
| www.qualys.com/2024/01/30/cve-2023-6246/syslog.txt | af854a3a-2127-422b-91ae-364da2661108 | www.qualys.com | Third Party Advisory |
| security.netapp.com/advisory/ntap-20240223-0006 | af854a3a-2127-422b-91ae-364da2661108 | security.netapp.com | Third Party Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Qualys Threat Research Unit for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2023-12-08T00:00:00.000Z | Reported to Red Hat. |
| CNA | 2024-01-30T00:00:00.000Z | Made public. |
Legacy QID Mappings
- 200092 Ubuntu Security Notification for GNU C Library Vulnerabilities (USN-6620-1)
- 284891 Fedora Security Update for glibc (FEDORA-2024-07597a0fb3)
- 285008 Fedora Security Update for glibc (FEDORA-2024-aec80d6e8a)
- 379329 GNU C Library Multiple Vulnerabilities
- 6000458 Debian Security Update for glibc (DSA 5611-1)
- 6140255 AWS Bottlerocket Security Update for glibc (GHSA-cv8g-c92g-vjxg)
- 710851 Gentoo Linux glibc Multiple Vulnerabilities (GLSA 202402-01)