CVE-2026-63869 (GCVE-0-2026-63869)
Vulnerability from cvelistv5
Published
2026-07-19 14:18
Modified
2026-08-05 12:36
Severity ?
7.6 (High) - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap When parsing the radiotap header of an injected frame, ieee80211_parse_tx_radiotap() uses the IEEE80211_RADIOTAP_ANTENNA value directly as a shift count: info->control.antennas |= BIT(*iterator.this_arg); *iterator.this_arg is an 8-bit value taken straight from the frame supplied by userspace, so BIT() can be asked to shift by up to 255. That is undefined behaviour on the unsigned long and is reported by UBSAN: UBSAN: shift-out-of-bounds in net/mac80211/tx.c:2174:30 shift exponent 235 is too large for 64-bit type 'unsigned long' Call Trace: ieee80211_parse_tx_radiotap+0xadb/0x1950 net/mac80211/tx.c:2174 ieee80211_monitor_start_xmit+0xb1f/0x1250 net/mac80211/tx.c:2451 ... packet_sendmsg+0x3eb6/0x50f0 net/packet/af_packet.c:3109 info->control.antennas is a 2-bit bitmap (u8 antennas:2), so only antenna indices 0 and 1 can ever be represented. Ignore any larger value instead of shifting out of bounds.
References
Impacted products
Vendor Product Version
Linux Linux Version: ef246a1480cc484cd2aeda75737cb0848616ddf3
Version: ef246a1480cc484cd2aeda75737cb0848616ddf3
Version: ef246a1480cc484cd2aeda75737cb0848616ddf3
Version: ef246a1480cc484cd2aeda75737cb0848616ddf3
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mac80211/tx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/mac80211/tx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.94",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.94",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.36",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap\n\nWhen parsing the radiotap header of an injected frame,\nieee80211_parse_tx_radiotap() uses the IEEE80211_RADIOTAP_ANTENNA value\ndirectly as a shift count:\n\n\tinfo-\u003econtrol.antennas |= BIT(*iterator.this_arg);\n\n*iterator.this_arg is an 8-bit value taken straight from the frame\nsupplied by userspace, so BIT() can be asked to shift by up to 255. That\nis undefined behaviour on the unsigned long and is reported by UBSAN:\n\n  UBSAN: shift-out-of-bounds in net/mac80211/tx.c:2174:30\n  shift exponent 235 is too large for 64-bit type \u0027unsigned long\u0027\n  Call Trace:\n   ieee80211_parse_tx_radiotap+0xadb/0x1950 net/mac80211/tx.c:2174\n   ieee80211_monitor_start_xmit+0xb1f/0x1250 net/mac80211/tx.c:2451\n   ...\n   packet_sendmsg+0x3eb6/0x50f0 net/packet/af_packet.c:3109\n\ninfo-\u003econtrol.antennas is a 2-bit bitmap (u8 antennas:2), so only antenna\nindices 0 and 1 can ever be represented. Ignore any larger value instead\nof shifting out of bounds."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.6,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - The bug is in mac80211 WiFi frame injection (radiotap parsing on monitor-mode TX), reachable only on systems with WiFi hardware in monitor mode; per kernel CNA guidance, WiFi frame injection maps to Adjacent.\nAC:L - The attacker fully controls the injected radiotap header via sendmsg() on an AF_PACKET socket and can reliably set IEEE80211_RADIOTAP_ANTENNA to any 8-bit value to trigger the out-of-bounds shift.\nPR:L - Reaching the path requires CAP_NET_RAW to open AF_PACKET sockets and CAP_NET_ADMIN to create a monitor interface via nl80211; both capabilities are obtainable by an unprivileged user through user namespaces (unshare -Urn).\nUI:N - Exploitation requires no action from a victim user; the attacker injects crafted frames through their own local socket.\nS:U - Impact is confined to kernel memory and WiFi TX state within the same security authority; this is not a VM escape or cross-boundary sandbox breakout.\nC:H - The unchecked antenna index causes shift-out-of-bounds undefined behavior while parsing attacker-controlled data into the skb control block (ieee80211_tx_info), constituting kernel memory corruption that could be leveraged for information disclosure.\nI:H - The undefined-behavior shift result is ORed into a bitfield in skb-\u003ecb, corrupting injection control metadata in kernel memory; such corruption in the TX path is potentially exploitable for further memory writes or control-flow manipulation.\nA:L - The primary demonstrated impact is a UBSAN shift-out-of-bounds report rather than a demonstrated kernel panic, but undefined behavior during packet processing can still cause degraded or unpredictable system behavior."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:44.591Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f6d3dc8e8492bf8435e0b23c99472af7bafd6b44"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b40c59bab08f2a99abf969cc0bb92fa49de004b"
        },
        {
          "url": "https://git.kernel.org/stable/c/033ce021a220913ac02416fcb5ac883a9ff8b6c7"
        },
        {
          "url": "https://git.kernel.org/stable/c/6c0cf89f36ac0c0fd8687a4ccdce2efb23a9c663"
        }
      ],
      "title": "wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63869",
    "datePublished": "2026-07-19T14:18:38.426Z",
    "dateReserved": "2026-07-19T07:54:57.017Z",
    "dateUpdated": "2026-08-05T12:36:44.591Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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