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CVE-2023-39191VulnerabilityPublished Updated

CVE-2023-39191: Red Hat Enterprise Linux 9 · Improper Input Validation

Affects Red Hat Enterprise Linux 9Source CVE Database V5

0

Not known to be exploited · CVSS 8.2 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Oct 2023

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

What to do

AI-suggested

Organizations should prioritize applying official patches from Red Hat as soon as they become available to address CVE-2023-39191. Until patches are deployed, restrict CAP_BPF capability strictly to trusted administrators and processes, minimizing the number of users who can load or manipulate eBPF programs. Implement strict access controls and auditing on systems running RHEL 9 to detect unusual use of eBPF-related capabilities. Employ kernel security modules (e.g., SELinux) to enforce policies limiting eBPF program loading and execution. Regularly monitor system logs and kernel events for suspicious activity related to eBPF. Consider isolating critical workloads and employing defense-in-depth strategies such as network segmentation to limit the impact of potential compromises. Additionally, maintain up-to-date inventories of systems running RHEL 9 to ensure comprehensive patch management. Engage in threat hunting focused on kernel-level anomalies and privilege escalation attempts. Finally, educate system administrators about the risks associated with CAP_BPF privileges and the importance of least privilege principles.

Description

An improper input validation flaw was found in the eBPF subsystem in the Linux kernel. The issue occurs due to a lack of proper validation of dynamic pointers within user-supplied eBPF programs prior to executing them. This may allow an attacker with CAP_BPF privileges to escalate privileges and execute arbitrary code in the context of the kernel.

References

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