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CVE-2023-6246

Glibc: heap-based buffer overflow in __vsyslog_internal()

8.4 HighPublic exploitFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

4.79%Up 4.8 points since Feb 8, 2024
90%50%10%1%

What each source reports

CVE List Score used 8.4

Glibc: heap-based buffer overflow in __vsyslog_internal()

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.

Record
CVE-2023-6246
CVSS 3.1
8.4 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-122
Updated
2026-11-02
EUVDEUVD-2023-58491 8.4

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.

Record
EUVD-2023-58491
CVSS 3.1
8.4 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-p6rw-gvvh-q8v4 8.4

A heap-based buffer overflow was found in the __vsyslog_internal function of the glibc library....

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.

Record
GHSA-p6rw-gvvh-q8v4
CVSS 3.1
8.4 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-122, CWE-787
Updated
2026-11-02
NVD 8.4

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.

Record
CVE-2023-6246
CVSS 3.1
8.4 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-122, CWE-787
Updated
2026-11-02
OSVAZL-34735 7.8

CVE-2023-6246 affecting package glibc for versions less than 2.38-6

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.

Record
AZL-34735
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVBELL-CVE-2023-6246 7.8
Record
BELL-CVE-2023-6246
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
Show 5 moreShow less
OSV 8.4

Glibc: heap-based buffer overflow in __vsyslog_internal()

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.

Record
CVE-2023-6246
CVSS 3.1
8.4 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-122
Updated
2026-11-02
OSVDEBIAN-CVE-2023-6246 7.8

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.

Record
DEBIAN-CVE-2023-6246
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2023-6246 7.8

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.

Record
UBUNTU-CVE-2023-6246
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1
8.4 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVMGASA-2024-0026 No score

Updated glibc packages fix security vulnerabilities

The updated packages fix security vulnerabilities: 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. (CVE-2023-6246) 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. (CVE-2023-6779) An integer 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 very long message, leading to an incorrect calculation of the buffer size to store the message, resulting in undefined behavior. (CVE-2023-6780)

Record
MGASA-2024-0026
Updated
2026-11-02
OSVopenSUSE-SU-2024:13647-1 No score

glibc-2.39-1.2 on GA media

These are all security issues fixed in the glibc-2.39-1.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:13647-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
glibc
Azure Linux:3
 before 2.38-6
2.38-6
glibc
Alpaquita:23
 2.37.0-r9 up to 2.37.0-r10
2.37.0-r10
glibc
Alpaquita:stream
 2.37.0-r9 up to 2.37.0-r10
2.37.0-r10
glibc
BellSoft Hardened Containers:23
 2.37.0-r9 up to 2.37.0-r10
2.37.0-r10
glibc
BellSoft Hardened Containers:stream
 2.37.0-r9 up to 2.37.0-r10
2.37.0-r10
glibc
Debian:12
 before 2.36-9+deb12u4, plus listed versions
2.36-92.36-9+deb12u12.36-9+deb12u22.36-9+deb12u3
2.36-9+deb12u4
glibc
Debian:13
 before 2.37-15
2.37-15
glibc
Debian:14
 before 2.37-15
2.37-15
glibc
Mageia:9
 before 2.36-52.mga9
2.36-52.mga9
glibc
Ubuntu:24.04:LTS
 before 2.39-0ubuntu1, plus listed versions
2.38-1ubuntu62.38-3ubuntu1
2.39-0ubuntu1
glibc
openSUSE:Tumbleweed
 before 2.39-1.2
2.39-1.2

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
SourceLinkDate
PoC in GitHubSimoesCTT/CTT-Vsyslog-Vortex-CVE-2023-62462026-04-06
PoC in GitHubelpe-pinillo/CVE-2023-62462024-03-02

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-6246 is a high vulnerability (CVSS 8.4) in Gnu Glibc, published January 30, 2024. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 4.79%, the 91st percentile. Fixed in glibc 2.38-6.

References

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