CVE-2026-53398
Description
A flaw was found in the Linux kernel's Network File System Daemon (NFSD). The nfsd4_decode_secinfo_no_name() function does not properly initialize a pointer (sin_exp) before processing an incoming data stream. If the data stream is malformed or truncated, the uninitialized pointer can retain stale data from previous operations. This can lead to an improper cleanup operation, potentially causing system instability or a denial of service.
Statement
A flaw in the Linux kernel's Network File System Daemon (NFSD) has been rated by Red Hat Product Security as having an impact of IMPORTANT. When the NFSv4 server decodes a truncated or malformed SECINFO_NO_NAME operation, nfsd4_decode_secinfo_no_name() returns an error before the sin_exp pointer is initialized. Because the inline iops argument buffer is no longer cleared between RPC calls, sin_exp can retain stale contents from a previous operation, and the error cleanup path then calls exp_put() on that stale pointer. Successful exploitation of this flaw can cause a kernel panic, resulting in a denial of service of the NFS server. Affected Red Hat products include Red Hat Enterprise Linux 9 and 10 (kernel and kernel-rt) and Red Hat In-Vehicle OS 2 and 2.1 (kernel and kernel-ivos-qualcomm), for which fixes are being pursued. Older Red Hat Enterprise Linux streams (RHEL 7 ELS, RHEL 8, and RHEL 9.2) are not affected because the vulnerable code is not present in those releases, and affectedness for RHEL 6 ELS is still under evaluation. Red Hat's severity rating of IMPORTANT (CVSS 3.1 score of 7.0) is lower than the CRITICAL rating (9.8) in the upstream CVE record; Red Hat's scoring reflects a more constrained attack vector, higher attack complexity, and privileges required compared with the upstream record's network, unauthenticated, low-complexity assumptions.
Mitigation
Mitigation for this issue is either not available or the currently available options do not 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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7 | N/A | 9.8 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | High | 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 | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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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