Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:HSummary
CVE-2024-6409 is a high-severity Signal Handler Race Condition (CWE-364) vulnerability in Almalinux (inferred from references). Its CVSS base score is 7.0 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
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.
A race condition vulnerability exists in OpenSSH's server component sshd, tracked as CVE-2024-6409. When a client fails to authenticate within a configured time window, the SIGALRM handler executes asynchronously and invokes functions such as syslog() that are not async-signal-safe, creating conditions that can corrupt process state.
An unauthenticated remote attacker can trigger the flaw by simply withholding authentication long enough to fire the alarm. In the worst case this leads to remote code execution with the privileges of the unprivileged user under which sshd runs, although successful exploitation requires winning a narrow timing window reflected in the CVSS attack-complexity rating of high.
Multiple Red Hat advisories (RHSA-2024:4457, RHSA-2024:4613, RHSA-2024:4716, RHSA-2024:4910, RHSA-2024:4955) address the issue through updated OpenSSH packages; administrators should apply the relevant errata for their distributions to eliminate the unsafe signal handling.
The EPSS score currently sits at 0.7640 with a recorded peak of 0.7673, indicating sustained but not sharply increasing public interest in exploitation since disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-47983
Vulnerability Data
A race condition vulnerability was discovered in how signals are handled by OpenSSH's server (sshd). If a remote attacker does not authenticate within a set time period, then sshd's SIGALRM handler is called asynchronously. However, this signal handler calls various…
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functions that are not async-signal-safe, for example, syslog(). As a consequence of a successful attack, in the worst case scenario, an attacker may be able to perform a remote code execution (RCE) as an unprivileged user running the sshd server.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
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.
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.
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.