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CVE Record

CVE-2024-26615: net/smc: fix illegal rmb_desc access in SMC-D connection dump

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix illegal rmb_desc access in SMC-D connection dump A crash was found when dumping SMC-D connections. It can be reproduced by following steps: - run nginx/wrk test: smc_run nginx smc_run wrk -t 16 -c 1000 -d <duration> -H 'Connection: Close' <URL> - continuously dump SMC-D connections in parallel: watch -n 1 'smcss -D' BUG: kernel NULL pointer dereference, address: 0000000000000030 CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G E 6.7.0+ #55 RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] Call Trace: <TASK> ? __die+0x24/0x70 ? page_fault_oops+0x66/0x150 ? exc_page_fault+0x69/0x140 ? asm_exc_page_fault+0x26/0x30 ? __smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] ? __kmalloc_node_track_caller+0x35d/0x430 ? __alloc_skb+0x77/0x170 smc_diag_dump_proto+0xd0/0xf0 [smc_diag] smc_diag_dump+0x26/0x60 [smc_diag] netlink_dump+0x19f/0x320 __netlink_dump_start+0x1dc/0x300 smc_diag_handler_dump+0x6a/0x80 [smc_diag] ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] sock_diag_rcv_msg+0x121/0x140 ? __pfx_sock_diag_rcv_msg+0x10/0x10 netlink_rcv_skb+0x5a/0x110 sock_diag_rcv+0x28/0x40 netlink_unicast+0x22a/0x330 netlink_sendmsg+0x1f8/0x420 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x160 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 ? __handle_mm_fault+0x2b0/0x6c0 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x69/0x180 entry_SYSCALL_64_after_hwframe+0x6e/0x76 It is possible that the connection is in process of being established when we dump it. Assumed that the connection has been registered in a link group by smc_conn_create() but the rmb_desc has not yet been initialized by smc_buf_create(), thus causing the illegal access to conn->rmb_desc. So fix it by checking before dump.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-26615 is a Linux kernel crash bug in SMC-D connection diagnostics. When SMC-D connections are being listed while a connection is still being set up, the kernel can dereference missing connection state and crash. The main business concern is availability on systems using SMC-D, not confirmed data theft or remote code execution.

Executive priority

Prioritize patching where SMC-D is used in production or where kernel crashes would materially affect service availability. Treat as routine-to-expedited kernel maintenance unless local evidence shows exposed SMC-D diagnostics, repeated crashes, or critical workload dependency.

Technical view

The flaw is an illegal access to conn->rmb_desc in the smc_diag SMC-D connection dump path. The source states a connection may be registered in a link group before rmb_desc is initialized, causing a NULL pointer dereference during diagnostic dumping. Kernel stable commits add a check before dumping that state.

Likely exposure

Exposure is likely limited to Linux systems with SMC-D enabled or in use, especially where SMC diagnostic tooling is available during high connection churn. The source lists Linux as affected and provides stable kernel fixes, but exact distribution package exposure must be checked with vendor advisories.

Exploitation context

The bundle does not show KEV listing or active exploitation. The described trigger involves dumping SMC-D connection state while SMC-D connections are being established. This supports a denial-of-service concern through kernel crash, but the provided evidence does not support code execution or data compromise.

Researcher notes

Evidence is strongest for a race or initialization-order bug in the SMC diagnostic dump path. The public record provides kernel commits and Debian LTS references, but no CVSS, CWE, KEV entry, or active exploitation claim. Validate against the exact stable or distribution kernel branch.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Check Debian LTS advisories if running Debian-based systems.
  • Confirm whether SMC-D is enabled or operationally required.
  • Restrict diagnostic access to trusted administrators.
  • Monitor vendor guidance for exact fixed package versions.

Validation and detection

  • Inventory Linux kernel versions on systems using SMC-D.
  • Check vendor advisories for CVE-2024-26615 fixed builds.
  • Verify the deployed kernel includes the stable fix commit for its branch.
  • Review logs for SMC diagnostic crashes or kernel NULL pointer faults.
  • Confirm SMC diagnostic tooling access is limited to authorized users.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
3Timeline events
2ADP providers
11Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542d, 4b1b7d3b30a6d32ac1a1dcede284e76ef8a8542dunaffected
LinuxLinux4.19, 0, 4.19.307, 5.4.269, 5.10.210, 5.15.149, 6.1.76, 6.6.15, 6.7.3, 6.8affected
Weakness

CWE details

No CWE listed

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