Security readout for executives and security teams
Plain-English summary
CVE-2021-47076 is a Linux kernel flaw in the software RDMA RXE driver. When RXE mishandles an invalid local key during an RDMA operation, the kernel can panic. The business impact is mainly service availability on systems using RDMA RXE, not evidence of data theft.
Executive priority
Prioritize as moderate where RDMA RXE is present on production Linux hosts. It is less urgent for systems without RDMA RXE. The main risk is availability disruption from kernel panic, with no source-bundle evidence of active exploitation.
Technical view
The RDMA RXE code failed to update WQE status on LOCAL_WRITE failures. The source describes a kernel panic when an atomic operation used an invalid lkey. Stable kernel commits are referenced as fixes; no CVSS, CWE, or exploit details are provided in the bundle.
Likely exposure
Exposure is most likely on Linux systems with RDMA RXE enabled or loaded. The bundle lists Linux kernel versions as affected, including entries around 4.8, 5.10.241, 5.12.7, and 5.13, but exact distro exposure depends on vendor backports.
Exploitation context
The bundle does not show CISA KEV status or other evidence of active exploitation. The described failure condition is an invalid RDMA local key reaching RXE handling and causing a kernel panic, so treat it as a potential local or RDMA-adjacent denial-of-service issue where RXE is available.
Researcher notes
Evidence is limited to the CVE text, kernel stable references, and a Debian LTS advisory link. The record lacks CVSS, CWE, and detailed affected-version semantics. Avoid assuming broader RDMA hardware exposure without confirming RXE module use and distribution patch status.
Mitigation direction
- Apply vendor kernel updates that include the referenced stable RXE fixes.
- Check Linux distribution advisories for backported kernel packages.
- Disable or avoid loading RDMA RXE where it is not required.
- Prioritize hosts that expose RDMA workloads or load rdma_rxe.
Validation and detection
- Inventory systems for loaded rdma_rxe and related RDMA modules.
- Map kernel versions to distro advisories and backport status.
- Confirm patched kernels include the referenced stable commits or vendor equivalent.
- Review crash logs for rxe_completer or rdma_rxe kernel panics.
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.
CVE-2021-47076 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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
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/a81e72d49b0648f68ab201163dbfc7841056d7a2CVE reference, Linux
- https://git.kernel.org/stable/c/abe31d25facdb9109fe2cf69890748295291570cCVE reference, Linux
- https://git.kernel.org/stable/c/dc07628bd2bbc1da768e265192c28ebd301f509dCVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlCVE reference, CVE
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.