{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "03556e4d0dbbbf4af9df76f4a3839c86f6afb015"
            },
            {
              "fixed": "3a2b378b3a9ca75d3518d879148d2ad25b5714a9"
            },
            {
              "fixed": "7a831bcd0486788283ef35e396d4282ee01bb0d5"
            },
            {
              "fixed": "ff976ef7c39199ebff33c18034636595016db9f0"
            },
            {
              "fixed": "e28e7fd34c449028325322a3f5127b92594b7396"
            },
            {
              "fixed": "993fd674fe85d114e6a8d3963033d4fbbc2170a8"
            },
            {
              "fixed": "bd968bdd568beacfdf98ec537a87527e85f1d0cf"
            },
            {
              "fixed": "86d531337ea1ba02d9f2bc830d07c683d9bfaade"
            },
            {
              "fixed": "84a04eb5b210643bd67aab81ff805d32f62aa865"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.16.0"
            },
            {
              "fixed": "5.10.260"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.211"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.177"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.144"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.95"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.38"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63831.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmac802154: llsec: add skb_cow_data() before in-place crypto\n\nllsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),\nllsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform\nin-place cryptographic transformations on skb data.  They build a\nscatterlist with sg_init_one() pointing into the skb's linear data area\nand then pass the same scatterlist as both src and dst to the crypto API\n(e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt).\n\nOn the RX path, __ieee802154_rx_handle_packet() clones the received skb\nbefore handing it to each subscriber via ieee802154_subif_frame().  The\ncloned skb shares the same underlying data buffer via reference\ncounting.  When llsec_do_decrypt() subsequently modifies this shared\nbuffer in place, it corrupts data that other clones -- potentially\nbelonging to other sockets or subsystems -- still reference.\n\nOn the TX path, similar data sharing can occur when an skb's head has\nbeen cloned (skb_cloned() returns true).\n\nThe fix is to call skb_cow_data() before performing any in-place crypto\noperation.  skb_cow_data() ensures that the skb's data area is not\nshared: if the skb head is cloned or the data spans multiple fragments,\nit copies the data into a private buffer that can be safely modified in\nplace.  This is the same pattern used by:\n\n  - ESP (net/ipv4/esp4.c, net/ipv6/esp6.c)\n  - MACsec (drivers/net/macsec.c)\n  - WireGuard (drivers/net/wireguard/receive.c)\n  - TIPC (net/tipc/crypto.c)\n\nWithout this guard, in-place crypto on shared skb data leads to:\n  - Silent data corruption of other skb clones\n  - Use-after-free when the crypto API scatterwalk writes through a\n    page that has already been freed by another clone's kfree_skb()\n  - Kernel crashes under concurrent 802.15.4 traffic with security\n    enabled (KASAN/KMSAN reports slab-use-after-free)\n\nFound by 0sec (https://0sec.ai) using automated source analysis.",
  "id": "CVE-2026-63831",
  "modified": "2026-07-22T05:30:06.233842470Z",
  "published": "2026-07-19T12:02:24.320Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a2b378b3a9ca75d3518d879148d2ad25b5714a9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7a831bcd0486788283ef35e396d4282ee01bb0d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/84a04eb5b210643bd67aab81ff805d32f62aa865"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86d531337ea1ba02d9f2bc830d07c683d9bfaade"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/993fd674fe85d114e6a8d3963033d4fbbc2170a8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bd968bdd568beacfdf98ec537a87527e85f1d0cf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e28e7fd34c449028325322a3f5127b92594b7396"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff976ef7c39199ebff33c18034636595016db9f0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63831.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63831"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "mac802154: llsec: add skb_cow_data() before in-place crypto"
}