CVE-2026-80863
Description
A flaw was found in the Linux kernel's RDMA/rxe component. A local user could exploit a memory corruption vulnerability in the free_rd_atomic_resources() function by updating the max_dest_rd_atomic value before the old array is properly freed, leading to an out-of-bounds write. This issue can cause a system crash, resulting in a denial of service (DoS).
Statement
An OOB write in RDMA/RXE free_rd_atomic_resources can occur because qp attr max_dest_rd_atomic is updated before the old rd atomic resources array is freed. The free path then uses the new larger bound while walking the old smaller allocation, which can write past the kmalloc object and corrupt slab memory. The issue is not directly network reachable because the triggering operation is a local uverbs control path rather than inbound RDMA traffic.
Mitigation
To mitigate this issue, prevent module rdma_rxe from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
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 | 7.3 | 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 | Low | N/A | N/A |
| Integrity Impact | High | 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:L/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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