CVE-2026-23397
Description
A flaw was found in the nfnetlink_osf module of the Linux kernel. A remote attacker could send specially crafted network packets containing malformed options, such as zero-length options or a Maximum Segment Size (MSS) option with an invalid length. This could lead to a system crash, resulting in a Denial of Service (DoS), which makes the system unavailable to legitimate users.
Statement
Exploitation of this vulnerability requires CAP_NET_ADMIN privileges to load the malicious OS fingerprint via nfnl_osf_add_callback(). Network packets then trigger the crash during fingerprint matching. Since setting up the vulnerable condition requires elevated privileges, and the impact is limited to denial of service, the risk is reduced compared to a purely remote attack.
Mitigation
To mitigate this issue, prevent the nfnetlink_osf and xt_osf modules from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | 7.1 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | Required | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | High | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity
Technical Impact: Read Memory; Modify Memory; Varies by Context
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