Security readout for executives and security teams
Plain-English summary
A Linux kernel race can cancel an SMC connection’s cleanup task before that task is initialized, producing a kernel warning and potentially disrupting availability. The supplied CVSS score is 7.5, driven by possible availability loss. No confidentiality or integrity impact is identified.
Executive priority
Prioritize remediation on production systems using SMC, especially where availability is important or RDMA drivers change during operation. Treat non-SMC systems as lower urgency after confirming the subsystem is unused. There is no supplied evidence of active exploitation, so response should be risk-based rather than emergency-wide shutdown.
Technical view
During SMC link-group termination, smc_close_cancel_work may call cancel_work_sync on conn->close_work before smc_close_init initializes it. This can reach __flush_work and trigger WARN_ON(!work->func). The kernel fix initializes close_work before connection establishment, removing the unsafe ordering.
Likely exposure
Exposure is limited to affected Linux kernels exercising SMC connection handling, particularly RDMA or ISM connection establishment concurrent with link-group termination. Driver removal is one documented trigger. The bundle lists affected identifiers including 4.12, 6.6.66, 6.12.5, and 6.13, but does not provide complete distribution-package mappings.
Exploitation context
The bundle reports no CISA KEV listing and provides no evidence of active exploitation or a public exploit. Although the supplied CVSS vector rates the attack vector as network-accessible, the description documents a concurrency condition involving SMC connection setup and termination. Reliable attacker control and resulting impact beyond the warning are not established here.
Researcher notes
The core issue is initialization ordering across concurrent SMC connection registration and link-group termination. The source demonstrates a WARN_ON reached by cancel_work_sync before INIT_WORK. It does not establish memory corruption, privilege escalation, data exposure, reliable remote denial of service, or exploitability details. Version assessment should use the relevant stable commit and distribution backport records.
Mitigation direction
- Apply a vendor-supported kernel containing the cited initialization fix.
- Check distribution advisories for package versions mapping to the stable-kernel commits.
- Prioritize systems actively using SMC with RDMA or ISM connectivity.
- If patching is delayed, consult vendor guidance for supported SMC exposure reduction.
Validation and detection
- Inventory running kernel versions on systems capable of using SMC.
- Determine whether SMC, RDMA, or ISM connection paths are actively used.
- Verify the installed kernel includes the applicable cited stable commit.
- Review kernel logs for __flush_work warnings involving smc_close_cancel_work.
- Retest normal SMC connection and termination behavior after updating.
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-2024-56641 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.
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.
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/f0c37002210aaede10dae849d1a78efc2243add2CVE reference, Linux
- https://git.kernel.org/stable/c/6638e52dcfafaf1b9cbc34544f0c832db0069ea1CVE reference, Linux
- https://git.kernel.org/stable/c/0541db8ee32c09463a72d0987382b3a3336b0043CVE reference, Linux
Products and packages named in the record
CWE details
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