{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-46954",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-46954",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2024-02-27T18:46:56.804Z",
    "updatedAt": "2026-05-11T13:45:08.606Z",
    "importedAt": "2026-10-24T01:56:36.661Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets\n\nwhen 'act_mirred' tries to fragment IPv4 packets that had been previously\nre-assembled using 'act_ct', splats like the following can be observed on\nkernels built with KASAN:\n\n BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60\n Read of size 1 at addr ffff888147009574 by task ping/947\n\n CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418\n Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014\n Call Trace:\n  <IRQ>\n  dump_stack+0x92/0xc1\n  print_address_description.constprop.7+0x1a/0x150\n  kasan_report.cold.13+0x7f/0x111\n  ip_do_fragment+0x1b03/0x1f60\n  sch_fragment+0x4bf/0xe40\n  tcf_mirred_act+0xc3d/0x11a0 [act_mirred]\n  tcf_action_exec+0x104/0x3e0\n  fl_classify+0x49a/0x5e0 [cls_flower]\n  tcf_classify_ingress+0x18a/0x820\n  __netif_receive_skb_core+0xae7/0x3340\n  __netif_receive_skb_one_core+0xb6/0x1b0\n  process_backlog+0x1ef/0x6c0\n  __napi_poll+0xaa/0x500\n  net_rx_action+0x702/0xac0\n  __do_softirq+0x1e4/0x97f\n  do_softirq+0x71/0x90\n  </IRQ>\n  __local_bh_enable_ip+0xdb/0xf0\n  ip_finish_output2+0x760/0x2120\n  ip_do_fragment+0x15a5/0x1f60\n  __ip_finish_output+0x4c2/0xea0\n  ip_output+0x1ca/0x4d0\n  ip_send_skb+0x37/0xa0\n  raw_sendmsg+0x1c4b/0x2d00\n  sock_sendmsg+0xdb/0x110\n  __sys_sendto+0x1d7/0x2b0\n  __x64_sys_sendto+0xdd/0x1b0\n  do_syscall_64+0x33/0x40\n  entry_SYSCALL_64_after_hwframe+0x44/0xae\n RIP: 0033:0x7f82e13853eb\n Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89\n RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\n RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb\n RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003\n RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010\n R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0\n R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0\n\n The buggy address belongs to the page:\n page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009\n flags: 0x17ffffc0001000(reserved)\n raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000\n raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n  ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00\n >ffff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2\n                                                              ^\n  ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2\n\nfor IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then,\nin the following call graph:\n\n  ip_do_fragment()\n    ip_skb_dst_mtu()\n      ip_dst_mtu_maybe_forward()\n        ip_mtu_locked()\n\nthe pointer to struct dst_entry is used as pointer to struct rtable: this\nturns the access to struct members like rt_mtu_locked into an OOB read in\nthe stack. Fix this changing the temporary variable used for IPv4 packets\nin sch_fragment(), similarly to what is done for IPv6 few lines below.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "c129412f74e99b609f0a8e95fc3915af1fd40f34",
              "status": "affected",
              "versionType": "git",
              "lessThan": "018bb8da5b5888e19585f9b802f036afe643fcef"
            },
            {
              "version": "c129412f74e99b609f0a8e95fc3915af1fd40f34",
              "status": "affected",
              "versionType": "git",
              "lessThan": "8e6dfb7beeb6489ac1365b8a71052e737f5da76e"
            },
            {
              "version": "c129412f74e99b609f0a8e95fc3915af1fd40f34",
              "status": "affected",
              "versionType": "git",
              "lessThan": "31fe34a0118e0acc958c802e830ad5d37ef6b1d3"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "5.11",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "5.11"
            },
            {
              "version": "5.11.20",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.11.*"
            },
            {
              "version": "5.12.3",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.12.*"
            },
            {
              "version": "5.13",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}