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NVD / CVE Program· CNA redhat

CVE-2023-6246: Glibc: heap-based buffer overflow in __vsyslog_internal()

Noroxi assessment

Priority: Monitor (action score 32/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 4.7% (FIRST EPSS); higher than 91.9% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: glibc (Debian:12) 2.36-9+deb12u4; glibc (Debian:13) 2.37-15; glibc (openSUSE:Tumbleweed) 2.39-1.2.

Low priority for now. Upgrade to glibc (Debian:12) 2.36-9+deb12u4; glibc (Debian:13) 2.37-15; glibc (openSUSE:Tumbleweed) 2.39-1.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.8 · v3.1—Proof of concept Fix available
Published
Jan 31, 2024
Updated
Oct 14, 2026
EPSS
4.7% · 91th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 4.7%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.8
CNA · redhat
8.4
0.6 point gap

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
gnuglibc
fedoraprojectfedora

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • fedoraproject fedora38
  • fedoraproject fedora39
  • gnu glibc2.36 and later · before 2.39

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Fedora Fedora

    • all versionsaffected

  • n/a glibc

    • 2.39not affected

  • Red Hat Red Hat Enterprise Linux 6

    • all versionsunknown
    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 7

    • all versionsunknown
    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 8

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 9

    • all versionsunknown

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12glibcbefore 2.36-9+deb12u42.36-9+deb12u4
Debian:13glibcbefore 2.37-152.37-15
openSUSE:Tumbleweedglibcbefore 2.39-1.22.39-1.2

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-4911Glibc: buffer overflow in ld.so leading to privilege escalationKEV
    80Now
  • CVE-2015-0235Heap-based buffer overflow in the __nss_hostname_digits_dots function in glibc 2.2, and other 2.x versions before 2.18, allows context-depen
    68This week
  • CVE-2015-7547Multiple stack-based buffer overflows in the (1) send_dg and (2) send_vc functions in the libresolv library in the GNU C Library (aka glibc
    60This week

Published before and after this one in the same product

  • ← EarlierCVE-2023-4806Sep 18, 2023 · Glibc: potential use-after-free in getaddrinfo()
    23Monitor
  • ← EarlierCVE-2023-5156Sep 25, 2023 · Glibc: dos due to memory leak in getaddrinfo.c
    30Monitor
  • Later →CVE-2023-6779Jan 31, 2024 · Glibc: off-by-one heap-based buffer overflow in __vsyslog_internal()
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:glibc2.36-9+deb12u4 · Debian:12Package registry (OSV)
opensuse:glibc2.39-1.2 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2023-6246 —
Proof-of-concept repository on GitHubstars:82024-03-02
Proof-of-concept repository on GitHubstars:02026-04-06

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+31 d
  3. TodayNov 7, 2026+1011 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2023-4911120 days apartGlibc: buffer overflow in ld.so leading to privilege escalationKEV
    80Now
  • CVE-2023-67790 days apartGlibc: off-by-one heap-based buffer overflow in __vsyslog_internal()
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-122 · Heap-based Buffer Overflow

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records