{
  "cveId": "CVE-2021-47238",
  "url": "https://patchblox.com/security/cve/CVE-2021-47238",
  "summary": "CVE-2021-47238 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47238, released May 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  net: ipv4: fix memory leak in ip_mc_add1_src  BU...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  net: ipv4: fix memory leak in ip_mc_add1_src  BUG: memory leak unreferenced object 0xffff888101bc4c00 (size 32):   comm \u0022syz-executor527\u0022, pid 360, jiffies 4294807421 (age 19.329s)   hex dump (first 32 bytes):     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................     01 00 00 00 00 00 00 00 ac 14 14 bb 00 00 02 00 ................   backtrace:     [\u003C00000000f17c5244\u003E] kmalloc include/linux/slab.h:558 [inline]     [\u003C00000000f17c5244\u003E] kzalloc include/linux/slab.h:688 [inline]     [\u003C00000000f17c5244\u003E] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline]     [\u003C00000000f17c5244\u003E] ip_mc_add_src\u002B0x95f/0xdb0 net/ipv4/igmp.c:2095     [\u003C000000001cb99709\u003E] ip_mc_source\u002B0x84c/0xea0 net/ipv4/igmp.c:2416     [\u003C0000000052cf19ed\u003E] do_ip_setsockopt net/ipv4/ip_sockglue.c:1294 [inline]     [\u003C0000000052cf19ed\u003E] ip_setsockopt\u002B0x114b/0x30c0 net/ipv4/ip_sockglue.c:1423     [\u003C00000000477edfbc\u003E] raw_setsockopt\u002B0x13d/0x170 net/ipv4/raw.c:857     [\u003C00000000e75ca9bb\u003E] __sys_setsockopt\u002B0x158/0x270 net/socket.c:2117     [\u003C00000000bdb993a8\u003E] __do_sys_setsockopt net/socket.c:2128 [inline]     [\u003C00000000bdb993a8\u003E] __se_sys_setsockopt net/socket.c:2125 [inline]     [\u003C00000000bdb993a8\u003E] __x64_sys_setsockopt\u002B0xba/0x150 net/socket.c:2125     [\u003C000000006a1ffdbd\u003E] do_syscall_64\u002B0x40/0x80 arch/x86/entry/common.c:47     [\u003C00000000b11467c4\u003E] entry_SYSCALL_64_after_hwframe\u002B0x44/0xae  In commit 24803f38a5c0 (\u0022igmp: do not remove igmp souce list info when set link down\u0022), the ip_mc_clear_src() in ip_mc_destroy_dev() was removed, because it was also called in igmpv3_clear_delrec().  Rough callgraph:  inetdev_destroy -\u003E ip_mc_destroy_dev      -\u003E igmpv3_clear_delrec         -\u003E ip_mc_clear_src -\u003E RCU_INIT_POINTER(dev-\u003Eip_ptr, NULL)  However, ip_mc_clear_src() called in igmpv3_clear_delrec() doesn\u0027t release in_dev-\u003Emc_list-\u003Esources. And RCU_INIT_POINTER() assigns the NULL to dev-\u003Eip_ptr. As a result, in_dev cannot be obtained through inetdev_by_index() and then in_dev-\u003Emc_list-\u003Esources cannot be released by ip_mc_del1_src() in the sock_close. Rough call sequence goes like:  sock_close -\u003E __sock_release    -\u003E inet_release       -\u003E ip_mc_drop_socket          -\u003E inetdev_by_index          -\u003E ip_mc_leave_src             -\u003E ip_mc_del_src                -\u003E ip_mc_del1_src  So we still need to call ip_mc_clear_src() in ip_mc_destroy_dev() to free in_dev-\u003Emc_list-\u003Esources.",
  "published": "2024-05-21T15:15:13Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00236,
  "epssPercentile": 0.14704,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47238",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47238",
      "released": "2024-05-21T15:15:13Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47238",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47238",
      "released": "2024-05-21T15:15:13Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47238",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47238",
      "released": "2024-05-21T15:15:13Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}