net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint

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Summary

CVECVE-2026-52941
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-24 08:16:24 UTC
Updated2026-07-08 19:10:24 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint The smc_msg_event tracepoint class, shared by smc_tx_sendmsg and smc_rx_recvmsg, unconditionally dereferences smc->conn.lnk: __string(name, smc->conn.lnk->ibname) conn->lnk is only set for SMC-R; for SMC-D it is NULL. Other code on these paths already handles this (e.g. !conn->lnk in SMC_STAT_RMB_TX_SIZE_SMALL()). With the tracepoint enabled, the first sendmsg()/recvmsg() on an SMC-D socket crashes: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [...] RIP: 0010:strlen+0x1e/0xa0 Call Trace: trace_event_raw_event_smc_msg_event (net/smc/smc_tracepoint.h:44) smc_rx_recvmsg (net/smc/smc_rx.c:515) smc_recvmsg (net/smc/af_smc.c:2859) __sys_recvfrom (net/socket.c:2315) __x64_sys_recvfrom (net/socket.c:2326) do_syscall_64 The faulting address 0x3e0 is offsetof(struct smc_link, ibname), confirming the NULL ->lnk deref. Enabling the tracepoint requires root, but the trigger itself is unprivileged: socket(AF_SMC, ...) has no capability check, and SMC-D negotiation needs no admin step on s390 or on x86 with the loopback ISM device loaded. Log an empty device name for SMC-D instead of dereferencing NULL.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.001160000 probability, percentile 0.019250000 (date 2026-07-09)

Problem Types: CWE-476

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 68200112534bb2acd1d7117dc2d5c124868d866d git Not specified
CNA Linux Linux affected aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 720c76b930c52cd58f50eb6b10569d03dccc7959 git Not specified
CNA Linux Linux affected aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 b706d6d76a2a2793fe5ad0fbc2a75b6a460094ef git Not specified
CNA Linux Linux affected aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 d2ea0b8aef8746e147602eac87ca8538f4bc7e66 git Not specified
CNA Linux Linux affected aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 561cf66fa9b6c86dfe4e687d2d1aeaaa6739917f git Not specified
CNA Linux Linux affected aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 7bf563badd37cb796df5477d2b78bb64148a1268 git Not specified
CNA Linux Linux affected 5.16 Not specified
CNA Linux Linux unaffected 5.16 semver Not specified
CNA Linux Linux unaffected 6.1.175 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.142 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.92 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.34 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.11 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/720c76b930c52cd58f50eb6b10569d03dccc7959 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/68200112534bb2acd1d7117dc2d5c124868d866d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/d2ea0b8aef8746e147602eac87ca8538f4bc7e66 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/b706d6d76a2a2793fe5ad0fbc2a75b6a460094ef 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/561cf66fa9b6c86dfe4e687d2d1aeaaa6739917f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/7bf563badd37cb796df5477d2b78bb64148a1268 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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