Security readout for executives and security teams
Plain-English summary
This is a Linux kernel flaw in the software RDMA/RoCE driver. If queue-pair creation fails, cleanup can use uninitialized fields, causing a refcount underflow and use-after-free warning. The listed impact is limited but real across confidentiality, integrity, and availability.
Executive priority
Treat as a medium-priority kernel maintenance item. It is not shown as internet-exploitable or actively exploited, but affected systems with RDMA/rxe should receive normal security patching because kernel memory-safety bugs can affect system stability and isolation.
Technical view
The issue is in drivers/infiniband/sw/rxe queue-pair cleanup. rxe_qp_do_cleanup() assumed valid QP fields after creation, but rxe_qp_from_init() failure could leave garbage values. CVSS 3.1 is 5.3: local attack vector, low complexity, low privileges, no user interaction, unchanged scope, low CIA impact.
Likely exposure
Exposure is most relevant on Linux systems running affected kernel versions where RDMA/rxe software RoCE functionality is present or enabled. The source lists Linux versions from 4.8 through before fixed stable releases including 4.9.270, 4.14.234, 4.19.192, 5.4.122, 5.10.40, 5.12.7, and 5.13.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. The CVSS vector indicates local, low-privilege access is required. The included trace comes from syzkaller-style testing and shows a kernel warning path, not public weaponization.
Researcher notes
The evidence supports a failed-initialization cleanup bug in Linux RDMA/rxe. The source does not provide a CWE, exploit proof, or distribution-specific fixed packages. Validation should focus on kernel lineage, backport presence, and whether rxe functionality is reachable in the environment.
Mitigation direction
- Apply Linux kernel updates containing the referenced stable fixes or vendor backports.
- Check your Linux distribution advisory for the exact fixed package version.
- Prioritize hosts using RDMA, InfiniBand, or software RoCE/rxe functionality.
- If RDMA/rxe is unnecessary, review vendor guidance on disabling unused RDMA components.
Validation and detection
- Inventory kernel versions on systems that may use RDMA or rxe.
- Confirm the running kernel includes a cited stable commit or vendor backport.
- Check whether rxe or RDMA functionality is loaded or enabled.
- Review kernel logs for refcount warnings involving rxe_qp_do_cleanup or rxe_create_qp.
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-2021-47078 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
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
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:L/I:L/A:L1.83.4CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
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/c65391dd9f0a47617e96e38bd27e277cbe1c40b0CVE reference, Linux
- https://git.kernel.org/stable/c/6a8086a42dfbf548a42bf2ae4faa291645c72c66CVE reference, Linux
- https://git.kernel.org/stable/c/f3783c415bf6d2ead3d7aa2c38802bbe10723646CVE reference, Linux
- https://git.kernel.org/stable/c/a62225d951d77eb20208fed8fc199e0c9b1df08bCVE reference, Linux
- https://git.kernel.org/stable/c/2ee4d79c364914989c80de382c0b1a7259a7e4b3CVE reference, Linux
- https://git.kernel.org/stable/c/03344e843ab6dd3b3f2cadfb65ed910590856c70CVE reference, Linux
- https://git.kernel.org/stable/c/67f29896fdc83298eed5a6576ff8f9873f709228CVE 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.