Security readout for executives and security teams
Plain-English summary
This Linux kernel flaw can leak kernel memory during certain network nexthop notification cleanup paths. On affected systems, a local low-privilege attacker could potentially drive resource exhaustion and stability impact. The source does not show remote exploitation or confirmed in-the-wild abuse.
Executive priority
Treat as high priority for Linux fleets where local users, tenants, containers, or network automation can interact with kernel networking paths. It is not evidenced as internet-exploited, but availability and integrity impact make delayed kernel patching risky.
Technical view
The fix changes nexthop notifier unregistration to replay delete notifications for the listener being removed, matching registration behavior. The bug affected cleanup interactions involving nexthop objects and listeners such as mlxsw, netdevsim, and VXLAN, creating memory leaks during device reload or teardown flows.
Likely exposure
Exposure is most relevant to Linux systems running affected kernel versions or downstream builds containing the vulnerable nexthop notifier logic. CVSS lists local access and low privileges. Network-heavy hosts, systems using relevant drivers, and shared-user or containerized environments deserve earlier review.
Exploitation context
The provided sources cite syzkaller discovery and kernel memory leak evidence. KEV is false, and the bundle provides no evidence of public exploitation in the wild. Any exploitation assessment should remain local-resource-exhaustion focused unless vendor advisories say otherwise.
Researcher notes
The source describes a CWE-400 resource management issue in nexthop notification chain listener cleanup. The notable implementation change is taking RTNL during unregister and adjusting VXLAN unregister behavior to avoid deadlock. Evidence is limited to the CVE record and stable kernel commits.
Mitigation direction
- Apply Linux kernel updates containing the referenced stable fixes.
- Use distro vendor advisories to map fixes to supported kernel packages.
- Prioritize shared-user, container host, and network infrastructure systems.
- Monitor affected hosts for abnormal kernel memory growth or reload-related instability.
- Avoid relying on manual driver cleanup as a substitute for patched kernels.
Validation and detection
- Inventory kernel versions and downstream patch status across Linux assets.
- Confirm vendor packages include the stable commits referenced for this CVE.
- Identify systems using nexthop, devlink reload, mlxsw, netdevsim, or VXLAN functionality.
- Review kernel logs and monitoring for memory growth during network device lifecycle events.
- Track remediation through normal vulnerability management evidence, not production reproduction.
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-400: 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-2021-47371 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
- 7.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.
SSVC decision data
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:N/I:H/A:H1.85.2CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/741760fa6252628a3d3afad439b72437d4b123d9CVE reference, Linux
- https://git.kernel.org/stable/c/3106a0847525befe3e22fc723909d1b21eb0d520CVE reference, Linux
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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.