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Fencer Vulns
medium 5.3

CVE-2023-6780 json

Glibc: integer overflow in __vsyslog_internal()

published 2024-01-31 2 y ago modified 2026-10-14 25 d ago also EUVD-2023-58992

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

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. This issue affects glibc 2.37 and newer.

Patch / fix

  • gnu glibc 2.39
  • glibc Debian 12 2.36-9+deb12u4
  • glibc Debian 14, Debian 13 2.37-15

debian advisories DEBIAN-CVE-2023-6780

  • glibc Ubuntu 24.04 LTS 2.39-0ubuntu1

ubuntu advisories UBUNTU-CVE-2023-6780

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • glibc Azure Linux 3.0 2.38-6

azure linux advisories AZL-34737

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-6780 updated cvss 5.3

glibc: integer overflow in __vsyslog_internal()

  • Red Hat Enterprise Linux 6 nscd, glibc, glibc-utils, compat-glibc, glibc-common Red Hat Enterprise Linux 7 nscd, glibc, glibc-utils, compat-glibc, glibc-common Red Hat Enterprise Linux 8 nscd, glibc, libnsl, nss_db, nss_hesiod, glibc-utils, +7 more Red Hat Enterprise Linux 9 nscd, glibc, libnsl, nss_db, nss_hesiod, glibc-utils, +6 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-25-162-05 updated cvss 5.3

Siemens SIMATIC S7-1500 CPU family

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.5
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

2.69% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • packetstormsecurity.com http://packetstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.html referenced PoC, tagged "exploit" by a source, unverified
  • seclists.org http://seclists.org/fulldisclosure/2024/Feb/3 referenced PoC, tagged "exploit" by a source, unverified
  • openwall.com https://www.openwall.com/lists/oss-security/2024/01/30/6 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

  • n/a glibc
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Fedora Fedora
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-131 Incorrect Calculation of Buffer Size
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.