Security readout for executives and security teams
Plain-English summary
CVE-2022-50401 is a Linux kernel NFS server bug. In an NFSv4.1 error path, the kernel can release the same transport reference twice, causing refcount underflow and use-after-free behavior. Business impact is potential system compromise or outage on affected Linux systems running nfsd.
Executive priority
High priority for Linux NFS servers, shared compute hosts, and environments with untrusted local users. Schedule patching through the normal kernel maintenance process, faster where nfsd is enabled. There is no supplied evidence of active exploitation, so urgency should be risk-based rather than emergency-driven.
Technical view
The issue is in nfsd callback connection handling under NFSv4.1 when rpc_create fails. A transport reference is handed to cl_cb_conn.cb_xprt too early, so both client cleanup and caller error handling can call svc_xprt_put. The CVE maps this to CWE-415 with CVSS 7.8, AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Likely exposure
Most relevant exposure is Linux systems using affected kernels with the in-kernel NFS server enabled. The source data names Linux/Linux and stable kernel fixes, but the supplied affected-version ranges are not fully self-explanatory. Validate against the exact distribution kernel package and backport status.
Exploitation context
The bundle does not show CISA KEV listing or public active exploitation. CVSS indicates local attack vector with low privileges and no user interaction. Treat exploitability as plausible kernel memory-corruption risk, but do not assume remote unauthenticated exploitation from the supplied evidence.
Researcher notes
The core condition is a double svc_xprt_put after rpc_create failure in NFSv4.1 callback update handling. The crash trace shows refcount underflow and list corruption. Source evidence does not establish reachable trigger conditions beyond the CVSS local, low-privilege model.
Mitigation direction
- Update affected Linux kernel packages using vendor-supported security updates.
- Confirm vendor advisories include the relevant nfsd stable fix or backport.
- Prioritize NFS servers and multi-user Linux hosts first.
- Disable or restrict nfsd where it is not required.
- Monitor kernel logs for refcount underflow, use-after-free, or nfsd callback warnings.
Validation and detection
- Inventory Linux hosts running nfsd or exporting NFSv4.1 services.
- Record exact kernel versions, distribution packages, and vendor patch status.
- Check whether kernel fixes matching the listed stable commits are present.
- Review logs for svc_xprt_put, refcount_warn_saturate, and nfsd4 callback traces.
- Verify NFS exposure and local user access assumptions per host.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-415: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2022-50401 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/707bcca9616002d204091ca7c4d1d91151104332CVE reference
- https://git.kernel.org/stable/c/15fc60aa5bdcf6d5f93000d3d00579fc67632ee0CVE reference
- https://git.kernel.org/stable/c/9b4ae8c42d2ff09ed7c5832ccce5684c55e5ed23CVE reference
- https://git.kernel.org/stable/c/fddac3b4578d302ac9e51e7f03a9aae6254ae2a3CVE reference
- https://git.kernel.org/stable/c/c1207219a4bfa50121c9345d5d165470d0a82531CVE reference
- https://git.kernel.org/stable/c/a472f069ced8601979f53c13c0cf20236074ed46CVE reference
- https://git.kernel.org/stable/c/e2f9f03e4537f3fcc8fd2bdd3248530c3477a371CVE reference
- https://git.kernel.org/stable/c/d843ebd860c58a38e45527e8ec6516059f4c97f3CVE reference
- https://git.kernel.org/stable/c/3bc8edc98bd43540dbe648e4ef91f443d6d20a24CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Double Free
Double Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.