{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.176-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.94-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.13-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  netfilter: nf_log: validate MAC header was set before dumping it  The fallback path of dump_mac_header() guards the MAC header access only with \"skb-\u003emac_header != skb-\u003enetwork_header\", without checking skb_mac_header_was_set(). When the MAC header is unset, mac_header is 0xffff, so the test passes and skb_mac_header(skb) returns skb-\u003ehead + 0xffff, ~64 KiB past the buffer; the loop then reads dev-\u003ehard_header_len bytes out of bounds into the kernel log.  This is reachable via the netdev logger: nf_log_unknown_packet() calls dump_mac_header() unconditionally, and an skb sent through AF_PACKET with PACKET_QDISC_BYPASS reaches the egress hook with mac_header still unset (__dev_queue_xmit(), which would reset it, is bypassed).  Add the skb_mac_header_was_set() check the ARPHRD_ETHER path already uses, and replace the open-coded MAC header length test with skb_mac_header_len(). Only skbs with an unset MAC header are affected; valid ones are dumped as before.   BUG: KASAN: slab-out-of-bounds in dump_mac_header (net/netfilter/nf_log_syslog.c:831)  Read of size 1 at addr ffff88800ea49d3f by task exploit/148  Call Trace:   kasan_report (mm/kasan/report.c:595)   dump_mac_header (net/netfilter/nf_log_syslog.c:831)   nf_log_netdev_packet (net/netfilter/nf_log_syslog.c:938 net/netfilter/nf_log_syslog.c:963)   nf_log_packet (net/netfilter/nf_log.c:260)   nft_log_eval (net/netfilter/nft_log.c:60)   nft_do_chain (net/netfilter/nf_tables_core.c:285)   nft_do_chain_netdev (net/netfilter/nft_chain_filter.c:307)   nf_hook_slow (net/netfilter/core.c:619)   nf_hook_direct_egress (net/packet/af_packet.c:257)   packet_xmit (net/packet/af_packet.c:280)   packet_sendmsg (net/packet/af_packet.c:3114)   __sys_sendto (net/socket.c:2265)",
  "id": "DEBIAN-CVE-2026-52942",
  "modified": "2026-09-09T08:47:32.783833523Z",
  "published": "2026-06-24T08:16:24.490Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-52942"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-52942"
  ]
}