CVE-2026-97568
Description
A flaw was found in the Linux kernel's Multipath TCP (MPTCP) implementation. A local attacker could cause a denial of service (DoS) by exploiting an uninitialized memory access during connection handling. When processing connection requests using SYN cookies, the kernel copies uninitialized subflow state information instead of preserving the proper connection flags, leading to kernel instability and potential system crashes.
Statement
This vulnerability is rated as Moderate impact for Red Hat Enterprise Linux because exploitation requires local access and primarily results in system instability or denial of service, with no loss of confidentiality or data integrity. The flaw is triggered during Multipath TCP (MPTCP) SYN-cookie handling when copying uninitialized subflow state data. Systems not actively processing MPTCP traffic or where MPTCP is unused are not exposed during standard TCP operations.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory; Read Application Data
When reusing a resource such as memory or a program variable, the original contents may not have been cleared before it is sent to an untrusted party.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Instability
The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend, possibly leading to a crash.
Other
Technical Impact: Unexpected State; Varies by Context
The consequences vary depending on the type of resource and how it is used within the product.
Frequently Asked Questions
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