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CVE-2023-6246 Fedoraproject CVE debrief

CVE-2023-6246 is a high-severity flaw in glibc’s __vsyslog_internal path. Under a specific set of conditions, an application can trigger a heap-based buffer overflow when syslog/vsyslog is used without a prior openlog call, or when openlog is called with a NULL ident, and the program name derived from argv[0] is longer than 1024 bytes. The reported impact is application crash and, in some contexts, local privilege escalation. NVD lists the issue as published on 2024-01-31 and later modified on 2026-05-12.

Vendor
Fedoraproject
Product
Unknown
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2025-06-10
Original CVE updated
2026-05-14
Advisory published
2025-06-10
Advisory updated
2026-05-14

Who should care

Linux platform teams, distro maintainers, embedded vendors, and application owners that rely on glibc syslog/vsyslog logging. Pay particular attention to systems running glibc 2.36 through 2.39 and to Fedora 38/39 as listed by NVD.

Technical summary

NVD describes a heap-based buffer overflow in __vsyslog_internal, which is called by syslog and vsyslog. The vulnerable path appears when openlog has not been called, or was called with ident set to NULL, and the basename of argv[0] exceeds 1024 bytes. NVD’s CPE data marks glibc versions 2.36 through 2.39 as vulnerable, and also lists Fedora 38 and Fedora 39. The CVSS vector is AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, reflecting a local, no-privileges attack that can still have severe consequences.

Defensive priority

High. This is a local-memory-corruption issue in a core libc logging routine, with potential for both denial of service and privilege escalation in affected deployments.

Recommended defensive actions

  • Update glibc to a version that includes the vendor fix or distro backport on all affected systems.
  • Audit applications and services that call syslog/vsyslog, especially code paths that do not call openlog or pass NULL ident.
  • Review any software that can run with unusually long argv[0] basenames or wrapper-generated program names.
  • Prioritize patching on multi-user systems, shared hosts, and environments where local users can execute code.
  • Follow distro security advisories and package announcements for backported fixes, including Fedora and downstream vendor guidance.

Evidence notes

This debrief is based only on the supplied CVE/NVD corpus. The vulnerability description, affected version ranges, CVSS vector, and references all come from the provided source item. Timing references use the CVE published and modified timestamps from the corpus, not the debrief generation date. The corpus includes third-party advisories and exploit references, but no exploit details are reproduced here.

Sources and references

Verified primary and authoritative sources

  • CVE-2023-6246 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2023-6246

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2023-6246 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2023-6246

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.