{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "20c72bd5f5f902e5a8745d51573699605bf8d21c"
            },
            {
              "fixed": "a0148342badd8c9b2e46551766a27cb76c82e715"
            },
            {
              "fixed": "4dd262f875e87653df50b138de1390ab0628e6b7"
            },
            {
              "fixed": "6e4615164d185a26badb2f376a2449f4d174a5f0"
            },
            {
              "fixed": "0f22412a2f4fbbe0251c132abee045d15a90e5b6"
            },
            {
              "fixed": "0f7baa82a24813cdad0b06a6f8f07e4824af5ed5"
            },
            {
              "fixed": "dcf458120add64c96a6ef5cf719340453f6e6abf"
            },
            {
              "fixed": "4fd34669558085bcb589aa2078a13b0ca79e360d"
            },
            {
              "fixed": "34080db3e70ddf94c38512ad2331e3c3afca6cc1"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.37"
            },
            {
              "fixed": "5.10.259"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.210"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.176"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.143"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.94"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.36"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52939.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion\n\nrds_ib_xmit_atomic() always programs a masked atomic opcode\n(IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD)\nfor every RDS atomic cmsg.  But the completion-side switch in\nrds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked\natomic completion falls through to default and returns rm == NULL while\nsend-\u003es_op is left set.  rds_ib_send_cqe_handler() then dereferences the\nNULL rm via rm-\u003em_final_op, oopsing in softirq context.  An unprivileged\nAF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection\ntriggers it; on hardware that natively accepts masked atomics (mlx4,\nmlx5) no extra setup is needed.\n\n  RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR!\n  Oops: general protection fault [#1] SMP KASAN\n  KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]\n  RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282)\n  Call Trace:\n   \u003cIRQ\u003e\n   rds_ib_send_cqe_handler (net/rds/ib_send.c:282)\n   poll_scq (net/rds/ib_cm.c:274)\n   rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294)\n   tasklet_action_common (kernel/softirq.c:943)\n   handle_softirqs (kernel/softirq.c:573)\n   run_ksoftirqd (kernel/softirq.c:479)\n   \u003c/IRQ\u003e\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nHandle the masked atomic opcodes in the same case as the non-masked\nones: they map to the same struct rds_message.atomic union member, so\nthe existing container_of()/rds_ib_send_unmap_atomic() body is correct\nfor them.",
  "id": "CVE-2026-52939",
  "modified": "2026-07-10T03:54:48.507141117Z",
  "published": "2026-06-24T07:14:28.622Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0f22412a2f4fbbe0251c132abee045d15a90e5b6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0f7baa82a24813cdad0b06a6f8f07e4824af5ed5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/34080db3e70ddf94c38512ad2331e3c3afca6cc1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4dd262f875e87653df50b138de1390ab0628e6b7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fd34669558085bcb589aa2078a13b0ca79e360d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6e4615164d185a26badb2f376a2449f4d174a5f0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a0148342badd8c9b2e46551766a27cb76c82e715"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dcf458120add64c96a6ef5cf719340453f6e6abf"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52939.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52939"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "summary": "net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion"
}