CVE-2023-6779Network attack vector

Application crash via undersized syslog allocation

Published Jan 31, 2024 · Updated Jul 14, 2026

Heap buffer overflow in glibc 2.37 and newer allows remote attackers to crash applications through syslog or vsyslog calls. The __vsyslog_internal function uses a negative snprintf or vsnprintf return value when calculating allocation size, producing a buffer too small for the formatted output. Reachability requires attacker-influenced data to reach an application's logging call and make formatting fail; the grounded consequence is an application crash.

CVSS severity8.2
High
EPSS probability3.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap buffer overflow in glibc 2.37 and newer allows remote attackers to crash applications through syslog or vsyslog calls. The __vsyslog_internal function uses a negative snprintf or vsnprintf return value when calculating allocation size, producing a buffer too small for the formatted output. Reachability requires attacker-influenced data to reach an application's logging call and make formatting fail; the grounded consequence is an application crash.

The record

CVE
CVE-2023-6779
Published
Jan 31, 2024
Updated
Jul 14, 2026
Vendor
Fedora Project
Product
Fedora Linux
Classifications
CWE-122, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 31, 2024CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fedora Project · Fedora LinuxAffected versions are unavailable in this record.
Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*

Published CVSS scores

8.2Siemens ProductCERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo