Security readout for executives and security teams
Plain-English summary
This is a Linux kernel memory safety flaw in the QRTR MHI send path. A local attacker could potentially trigger use-after-free behavior and gain high impact over confidentiality, integrity, and availability. The source bundle does not show active exploitation or product-specific appliance exposure.
Executive priority
Prioritize normal high-severity kernel patching, especially on multi-user systems, developer workstations, and hosts running untrusted workloads. No source indicates emergency active exploitation, but kernel memory corruption can create broad compromise impact if reachable locally.
Technical view
The flaw is CWE-416 use-after-free. An MHI transmit callback may run immediately after an skb is queued, decrementing the socket reference and freeing the skb before later dereference/refcount handling. Kernel stable commits move skb dereference and socket refcount increment before queueing.
Likely exposure
Exposure is limited to systems running affected Linux kernel builds that include the vulnerable QRTR/MHI code path. The bundle lists Linux kernel 5.8-era affected code and stable fixes associated with 5.10.35, 5.11.19, 5.12.2, and 5.13. Distro backports must be verified.
Exploitation context
The CVSS vector is local, low complexity, no privileges, and no user interaction. The provided KEV field is false, and the bundle contains no evidence of active exploitation. Treat this as serious kernel risk where untrusted local code can run.
Researcher notes
Focus validation on kernel provenance, stable commit inclusion, and whether the QRTR/MHI path is built and reachable. The source bundle gives root cause and fix direction, but not exploitability details, affected distributions, or operational mitigations beyond applying fixed kernel code.
Mitigation direction
- Upgrade to a kernel containing the referenced stable fixes.
- Check Linux vendor or distribution advisories for backported fixed packages.
- Prioritize shared systems where untrusted local users or workloads run.
- If patching is delayed, reduce local code execution exposure where practical.
Validation and detection
- Inventory Linux kernel versions across servers, endpoints, and images.
- Confirm whether vendor kernels include the referenced stable commits or equivalent backports.
- Identify systems using kernel builds with QRTR/MHI support enabled.
- Run regression testing before production kernel rollout.
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-416: 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-2021-46973 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
- 8.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/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.
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:N/UI:N/S:U/C:H/I:H/A:H2.55.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
8.4HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/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/48ec949ac979b4b42d740f67b6177797af834f80CVE reference, Linux
- https://git.kernel.org/stable/c/ea474054c2cc6e1284604b21361f475c7cc8c0a0CVE reference, Linux
- https://git.kernel.org/stable/c/03c649dee8b1eb5600212a249542a70f47a5ab40CVE reference, Linux
- https://git.kernel.org/stable/c/47a017f33943278570c072bc71681809b2567b3aCVE 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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.