Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2024-6387 is a high-severity Signal Handler Race Condition (CWE-364) vulnerability in Freebsd Freebsd. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 0.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2024-6387 is a security regression of the earlier CVE-2006-5051 flaw in OpenSSH's sshd server component. It stems from a race condition that allows sshd to handle certain signals unsafely during authentication, specifically when a client fails to complete authentication within a defined time window.
An unauthenticated remote attacker can trigger the race condition over the network without any credentials or user interaction. Successful exploitation can lead to arbitrary code execution with root privileges on the affected server, as reflected in the CVSS 8.1 score covering high impact to confidentiality, integrity, and availability.
Red Hat has published multiple errata (RHSA-2024:4312, RHSA-2024:4340, RHSA-2024:4389, RHSA-2024:4469, and RHSA-2024:4474) that address the issue through updated OpenSSH packages; organizations should apply these patches promptly to eliminate the regression. The EPSS score has reached 0.6579 without evidence of a material rise from a low baseline.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-47981
Vulnerability Data
A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to…
more
authenticate within a set time period.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including concurrency and fuzz testing) can discover signal-handler race conditions before deployment.
Engineering principles such as least privilege, complete mediation, and avoidance of shared mutable state in handlers directly reduce introduction of signal-handler race conditions.
Maintaining separate execution domains for each process structurally eliminates unintended concurrent access to the same shared resources.
Preventing unintended information transfer through shared system resources directly addresses the improper concurrent modification that defines a race condition.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent introduction of signal-handler race conditions during coding and review.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect signal-handler race conditions before release.
Secure SDLC practices can require avoidance of unsafe signal handling patterns.
Application security requirements can specify thread-safety and locking rules, but do not prescribe implementation details.
Secure architecture principles can mandate safe concurrency and signal design.
Secure coding standards directly prohibit race-prone signal handlers.
Change management may catch unsafe signal code during reviews but does not address the weakness itself.