CVE-2026-80586
Description
A flaw was found in the Linux kernel's Multipath TCP (mptcp) implementation. A remote attacker could send specially crafted Data Sink Selection (DSS) options with an unexpected size. This could lead to data inconsistency or the access of uninitialized data, potentially resulting in information disclosure or a denial of service.
Mitigation
The vulnerability affects the Multipath TCP (MPTCP) feature in the Linux kernel. To mitigate this issue, MPTCP can be disabled by preventing the `mptcp` kernel module from loading. To disable the `mptcp` module: 1. Create a new file `/etc/modprobe.d/disable-mptcp.conf` with the following content: `install mptcp /bin/true
blacklist mptcp` 2. Regenerate the initramfs to ensure the change takes effect on boot: `sudo dracut -f -v` 3. Reboot the system for the changes to take effect. Disabling MPTCP may impact network performance or functionality for applications that rely on Multipath TCP.
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 | 8.3 | N/A | 9.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | Low | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the uninitialized pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the uninitialized pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the uninitialized pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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