CVE-2023-53680
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: NFSD: Avoid calling OPDESC() with ops->opnum == OP_ILLEGAL OPDESC() simply indexes into nfsd4_ops[] by the op's operation number, without range checking that value. It assumes callers are careful to avoid calling it with an out-of-bounds opnum value. nfsd4_decode_compound() is not so careful, and can invoke OPDESC() with opnum set to OP_ILLEGAL, which is 10044 -- well beyond the end of nfsd4_ops[].
Statement
NFSD could call OPDESC() with opnum == OP_ILLEGAL, indexing past nfsd4_ops[] and causing an out-of-bounds read leading to a crash. A remote unauthenticated NFSv4 client could trigger this via a crafted COMPOUND, impacting availability of the NFS server. The fix sets op->opdesc = NULL, assigns opdesc only when opnum is in range, and removes the unconditional OPDESC() call.
Mitigation
To mitigate this issue, prevent module nfs 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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 7.8 | 7.5 |
| Attack Vector | Network | Local | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | Low | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | High | None |
| Integrity Impact | None | High | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/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:N/I:N/A:H
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