CVE-2026-98952
Description
A flaw was found in the Linux kernel's Packet Forwarding Control Protocol (PFCP) component. A remote attacker can exploit this vulnerability by sending a truncated or fragmented PFCP packet with the session flag enabled, causing the kernel to read memory beyond the end of the packet buffer. This out-of-bounds read can lead to a Denial of Service (DoS) via a system crash or cause incorrect network traffic handling due to corrupted tunnel metadata.
Statement
Red Hat has evaluated this vulnerability as an Important severity flaw because an unauthenticated remote attacker could transmit malformed network packets over UDP to trigger an out-of-bounds read in the kernel, potentially causing a system crash or corrupting tunnel classification metadata. However, this flaw resides in the Packet Forwarding Control Protocol subsystem introduced in newer upstream kernels, which is not shipped in supported Red Hat Enterprise Linux kernels. Consequently, supported Red Hat Enterprise Linux releases are not affected by this vulnerability.
Mitigation
--- CME Mitigation Guidance (2026-11-02) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to ensure packet data is linearized up to the end of the SEID using pskb_may_pull before reading session headers in pfcp_session_recv: upgrade to the fixed release, which pull packet data up to the end of the SEID using pskb_may_pull, drop packets too short to contain it, and reload the header pointer, closing all 2 injection vectors (truncated PFCP packets with the session flag set, fragmented PFCP packets with session headers crossing packet buffer fragments). Until patched, this is only a concern on Linux systems configured to receive and process PFCP UDP packets — Supported Red Hat Enterprise Linux releases and non-Linux platforms are unaffected — so Restrict network routing and filter UDP traffic to block untrusted access to the target PFCP listener until patched. As a compensating measure, Enable runtime memory error detection such as KASAN or HWASan to detect out-of-bounds reads beyond the linear skb data buffer during PFCP session packet parsing. These controls limit blast radius and contain exploitation, but they do not fix the underlying out-of-bounds read defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-1005 Runtime Memory Error Detection (KASAN/HWASan) (medium)
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 | 7.5 | N/A | 7.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | Low |
| Integrity Impact | None | N/A | Low |
| Availability Impact | High | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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