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CVE-2026-52941

Full vulnerability record from the local CVENow database.

Description

In 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.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-24 08:16:24.380000
Last modified
2026-11-06 17:17:57.280000
View original CVE JSON 
{
  "id": "CVE-2026-52941",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-24T08:16:24.380",
  "lastModified": "2026-11-06T17:17:57.280",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint\n\nThe smc_msg_event tracepoint class, shared by smc_tx_sendmsg and\nsmc_rx_recvmsg, unconditionally dereferences smc->conn.lnk:\n\n\t__string(name, smc->conn.lnk->ibname)\n\nconn->lnk is only set for SMC-R; for SMC-D it is NULL. Other code on\nthese paths already handles this (e.g. !conn->lnk in\nSMC_STAT_RMB_TX_SIZE_SMALL()). With the tracepoint enabled, the first\nsendmsg()/recvmsg() on an SMC-D socket crashes:\n\n  Oops: general protection fault, probably for non-canonical address\n  KASAN: null-ptr-deref in range [...]\n  RIP: 0010:strlen+0x1e/0xa0\n  Call Trace:\n   trace_event_raw_event_smc_msg_event (net/smc/smc_tracepoint.h:44)\n   smc_rx_recvmsg (net/smc/smc_rx.c:515)\n   smc_recvmsg (net/smc/af_smc.c:2859)\n   __sys_recvfrom (net/socket.c:2315)\n   __x64_sys_recvfrom (net/socket.c:2326)\n   do_syscall_64\n\nThe faulting address 0x3e0 is offsetof(struct smc_link, ibname),\nconfirming the NULL ->lnk deref. Enabling the tracepoint requires\nroot, but the trigger itself is unprivileged: socket(AF_SMC, ...) has\nno capability check, and SMC-D negotiation needs no admin step on\ns390 or on x86 with the loopback ISM device loaded.\n\nLog an empty device name for SMC-D instead of dereferencing NULL."
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