Security readout for executives and security teams
Plain-English summary
A remotely supplied, oversized RDMA/rxe unreliable-datagram request can incorrectly force the receiving queue pair into an error state instead of being silently discarded. This can interrupt affected RDMA communications, creating an availability risk. The supplied CVSS score is 7.5, with no indicated confidentiality or integrity impact.
Executive priority
Treat as a high-priority availability issue where RDMA/rxe supports critical or network-accessible workloads. Establish exposure quickly, then apply vendor-supported fixed kernels during an expedited maintenance window. Lower the priority for systems where RDMA/rxe UD functionality is absent or inaccessible.
Technical view
Linux RDMA/rxe responder length validation regressed after commit 689c5421bfe0. When a UD packet exceeds the receive buffer, copy_data returns -EINVAL, send_data_in reports RESPST_ERR_MALFORMED_WQE, and the UD queue pair enters ERROR state. Correct behavior is to discard the invalid request and continue waiting.
Likely exposure
Exposure is limited to Linux systems using the RDMA/rxe subsystem with unreliable-datagram queue pairs. The bundle identifies affected versions including 6.2, 6.6.36, 6.9.7, and 6.10, but distribution backports may change actual status. Systems not using this functionality are unlikely to be practically exposed.
Exploitation context
The CVSS vector describes network-reachable, low-complexity, unauthenticated availability impact without user interaction. However, the bundle reports no CISA KEV listing and provides no evidence of active exploitation or a public exploit. Practical reachability depends on whether RDMA/rxe UD traffic is enabled and accessible.
Researcher notes
The flaw is a regression in responder handling, not a stated memory-corruption issue. Its documented consequence is transition of a UD queue pair into ERROR state after an oversized request cannot fit the receive buffer. The source bundle names three stable fix commits but does not map each commit to a specific release branch.
Mitigation direction
- Identify systems using Linux RDMA/rxe and unreliable-datagram queue pairs.
- Prioritize exposed or business-critical RDMA services for remediation.
- Obtain a distribution kernel containing the applicable upstream stable fix.
- Consult vendor guidance to account for kernel backports and release-specific versioning.
- Restrict unnecessary network access to affected RDMA services while remediation is pending.
Validation and detection
- Record running kernel versions on systems providing RDMA/rxe services.
- Confirm whether RDMA/rxe and unreliable-datagram queue pairs are actively used.
- Map distribution kernel builds against the three referenced stable fixes.
- Verify updated kernels include the applicable fix or documented vendor backport.
- Confirm UD queue pairs remain operational during approved resilience testing.
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
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ATT&CK lookup starting points
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CVE-2024-40992 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6LinuxVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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/163868ec1f6c610d16da9e458fe1dd7d5de97341CVE reference, Linux
- https://git.kernel.org/stable/c/943c94f41dfe36536dc9aaa12c9efdf548ceb996CVE reference, Linux
- https://git.kernel.org/stable/c/f67ac0061c7614c1548963d3ef1ee1606efd8636CVE 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.