CVE-2023-39976

log_blackbox.c in libqb before 2.0.8 allows a buffer overflow via long log messages because the header size is not considered.

Published: 2023-08-08 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-39976 is rated Moderate Risk (60.2/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.98%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-39976

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.17% 0.98% +0.82%
2 2025-11-21 0.63% 0.17% -0.46%
3 2025-11-18 — 0.63% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-39976

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]

Weakness enumeration for CVE-2023-39976

OS Trackers for CVE-2023-39976

vendor priority summary link
debian not yet assigned CVE-2023-39976 not yet assigned priority: Debian including 1 source packages (libqb), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2023-39976
redhat medium — https://access.redhat.com/security/cve/CVE-2023-39976
suse medium — https://www.suse.com/security/cve/CVE-2023-39976/
ubuntu medium CVE-2023-39976 medium priority: Ubuntu including 1 source packages (libqb), 7 status rows across 7 suites (bionic, focal, jammy, lunar, trusty, upstream, xenial): not-affected 4, released 2, needs-triage 1. https://ubuntu.com/security/CVE-2023-39976

Affected software / configurations for CVE-2023-39976

Vendor Product Version Raw CPE
clusterlabs libqb < 2.0.8 cpe:2.3:a:clusterlabs:libqb:*:*:*:*:*:*:*:*

References for CVE-2023-39976

cvelogic Threat Intelligence