CVE-2026-72220

Description

A flaw was found in the Linux kernel's sunrpc component. When a worker thread processes a new request and encounters an early error, a stale release hook can be re-triggered against previously used data. This can lead to a double-free or use-after-free vulnerability, potentially allowing an attacker to cause a denial of service or execute arbitrary code.

Statement

A stale rq_procinfo pointer in a reused SUNRPC server request object can cause svc_release_rqst() to invoke a previous pc_release callback against already released or reused RPC state, resulting in a double-free or use-after-free. A remote client may trigger the condition when a previous RPC installs a valid rq_procinfo and a subsequent request on the reused svc_rqst reaches an early error path, such as a short frame, unsupported protocol, or authentication failure, before a new procedure descriptor is installed.

For CVSS, AV:N/PR:N is used because an attacker can reach the vulnerable request-processing path remotely when an affected SUNRPC service is exposed, and the triggering error can occur before successful authentication. Practical exploitation has additional state-dependent complexity because it requires reuse of request state from a preceding RPC followed by an appropriate early-failing request. Exposure is primarily relevant to systems providing kernel SUNRPC services, such as NFS server deployments, which are commonly restricted to trusted storage or internal networks.

The directly supported impact is at least remote denial of service through kernel memory corruption and a possible crash. Because the underlying condition is a genuine double-free or use-after-free, confidentiality or integrity impact is possible in a paranoid worst-case assessment, although the patch does not demonstrate controlled memory corruption, information disclosure, privilege escalation, or remote code execution.

Mitigation

To reduce exposure to this vulnerability, disable the kernel NFS server if it is not required in your environment:

# systemctl stop nfs-server.service
# systemctl disable nfs-server.service

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 HatNVDcve.org
Base Score7N/A9.8
Attack VectorNetworkN/ANetwork
Attack ComplexityHighN/ALow
Privileges RequiredNoneN/ANone
User InteractionNoneN/ANone
ScopeUnchangedN/AUnchanged
ConfidentialityLowN/AHigh
Integrity ImpactLowN/AHigh
Availability ImpactHighN/AHigh

Vector

Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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)

Availability,Integrity

Technical Impact: DoS: Crash, Exit, or Restart

Integrity

Technical Impact: Modify Memory; Modify Application Data

Depending on the type of resource and the expected API behavior, this could lead to memory corruption, data corruption, or execution path corruption.

Frequently Asked Questions

Want to get errata notifications? Sign up here.