{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "7eb9282cd0efac08b8377cbd5037ba297c77e3f7"
            },
            {
              "fixed": "2e96e1bc9b4d5450e6c33f078e19a9bc1dda6c0b"
            },
            {
              "fixed": "d704ee9c7bc68a161684c51a7ac05b446dcf38d4"
            },
            {
              "fixed": "befb8968a2abdfa948d5600ea7f7a509a292a590"
            },
            {
              "fixed": "8a81e336da685423f5b64aac4d571e63d674c52a"
            },
            {
              "fixed": "c38d41134085193efd5b237cf513ad5b3421a60d"
            },
            {
              "fixed": "af1b7699466f6556b351fa25d3dc870abfb5d310"
            },
            {
              "fixed": "65ef7397eb9a296e91839f5fd10be96f23d332e7"
            },
            {
              "fixed": "a84b6fedbc97078788be78dbdd7517d143ad1a77"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.36"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "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-2026-52942.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_log: validate MAC header was set before dumping it\n\nThe fallback path of dump_mac_header() guards the MAC header access\nonly with \"skb-\u003emac_header != skb-\u003enetwork_header\", without checking\nskb_mac_header_was_set(). When the MAC header is unset, mac_header is\n0xffff, so the test passes and skb_mac_header(skb) returns\nskb-\u003ehead + 0xffff, ~64 KiB past the buffer; the loop then reads\ndev-\u003ehard_header_len bytes out of bounds into the kernel log.\n\nThis is reachable via the netdev logger: nf_log_unknown_packet() calls\ndump_mac_header() unconditionally, and an skb sent through AF_PACKET\nwith PACKET_QDISC_BYPASS reaches the egress hook with mac_header still\nunset (__dev_queue_xmit(), which would reset it, is bypassed).\n\nAdd the skb_mac_header_was_set() check the ARPHRD_ETHER path already\nuses, and replace the open-coded MAC header length test with\nskb_mac_header_len(). Only skbs with an unset MAC header are affected;\nvalid ones are dumped as before.\n\n BUG: KASAN: slab-out-of-bounds in dump_mac_header (net/netfilter/nf_log_syslog.c:831)\n Read of size 1 at addr ffff88800ea49d3f by task exploit/148\n Call Trace:\n  kasan_report (mm/kasan/report.c:595)\n  dump_mac_header (net/netfilter/nf_log_syslog.c:831)\n  nf_log_netdev_packet (net/netfilter/nf_log_syslog.c:938 net/netfilter/nf_log_syslog.c:963)\n  nf_log_packet (net/netfilter/nf_log.c:260)\n  nft_log_eval (net/netfilter/nft_log.c:60)\n  nft_do_chain (net/netfilter/nf_tables_core.c:285)\n  nft_do_chain_netdev (net/netfilter/nft_chain_filter.c:307)\n  nf_hook_slow (net/netfilter/core.c:619)\n  nf_hook_direct_egress (net/packet/af_packet.c:257)\n  packet_xmit (net/packet/af_packet.c:280)\n  packet_sendmsg (net/packet/af_packet.c:3114)\n  __sys_sendto (net/socket.c:2265)",
  "id": "CVE-2026-52942",
  "modified": "2026-08-12T03:51:25.507953884Z",
  "published": "2026-06-24T07:14:30.610Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2e96e1bc9b4d5450e6c33f078e19a9bc1dda6c0b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/65ef7397eb9a296e91839f5fd10be96f23d332e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8a81e336da685423f5b64aac4d571e63d674c52a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a84b6fedbc97078788be78dbdd7517d143ad1a77"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/af1b7699466f6556b351fa25d3dc870abfb5d310"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/befb8968a2abdfa948d5600ea7f7a509a292a590"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c38d41134085193efd5b237cf513ad5b3421a60d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d704ee9c7bc68a161684c51a7ac05b446dcf38d4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52942.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52942"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "netfilter: nf_log: validate MAC header was set before dumping it"
}