CVE-2025-21756 (GCVE-0-2025-21756)

Vulnerability from cvelistv5 – Published: 2025-02-27 02:18 – Updated: 2025-11-03 19:37
VLAI?
Title
vsock: Keep the binding until socket destruction
Summary
In the Linux kernel, the following vulnerability has been resolved: vsock: Keep the binding until socket destruction Preserve sockets bindings; this includes both resulting from an explicit bind() and those implicitly bound through autobind during connect(). Prevents socket unbinding during a transport reassignment, which fixes a use-after-free: 1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2) 2. transport->release() calls vsock_remove_bound() without checking if sk was bound and moved to bound list (refcnt=1) 3. vsock_bind() assumes sk is in unbound list and before __vsock_insert_bound(vsock_bound_sockets()) calls __vsock_remove_bound() which does: list_del_init(&vsk->bound_table); // nop sock_put(&vsk->sk); // refcnt=0 BUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730 Read of size 4 at addr ffff88816b46a74c by task a.out/2057 dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 __vsock_bind+0x62e/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Allocated by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 __vsock_create.constprop.0+0x2e/0xb60 vsock_create+0xe4/0x420 __sock_create+0x241/0x650 __sys_socket+0xf2/0x1a0 __x64_sys_socket+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 __vsock_bind+0x5e1/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e refcount_t: addition on 0; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150 RIP: 0010:refcount_warn_saturate+0xce/0x150 __vsock_bind+0x66d/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e refcount_t: underflow; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150 RIP: 0010:refcount_warn_saturate+0xee/0x150 vsock_remove_bound+0x187/0x1e0 __vsock_release+0x383/0x4a0 vsock_release+0x90/0x120 __sock_release+0xa3/0x250 sock_close+0x14/0x20 __fput+0x359/0xa80 task_work_run+0x107/0x1d0 do_exit+0x847/0x2560 do_group_exit+0xb8/0x250 __x64_sys_exit_group+0x3a/0x50 x64_sys_call+0xfec/0x14f0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < e7754d564579a5db9c5c9f74228df5d6dd6f1173 (git)
Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < e48fcb403c2d0e574c19683f09399ab4cf67809c (git)
Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < 42b33381e5e1f2b967dc4fb4221ddb9aaf10d197 (git)
Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < 3f43540166128951cc1be7ab1ce6b7f05c670d8b (git)
Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < 645ce25aa0e67895b11d89f27bb86c9d444c40f8 (git)
Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < b1afd40321f1c243cffbcf40ea7ca41aca87fa5e (git)
Affected: c0cfa2d8a788fcf45df5bf4070ab2474c88d543a , < fcdd2242c0231032fc84e1404315c245ae56322a (git)
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    Linux Linux Affected: 5.5
Unaffected: 0 , < 5.5 (semver)
Unaffected: 5.10.235 , ≤ 5.10.* (semver)
Unaffected: 5.15.179 , ≤ 5.15.* (semver)
Unaffected: 6.1.131 , ≤ 6.1.* (semver)
Unaffected: 6.6.79 , ≤ 6.6.* (semver)
Unaffected: 6.12.16 , ≤ 6.12.* (semver)
Unaffected: 6.13.4 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock: Keep the binding until socket destruction\n\nPreserve sockets bindings; this includes both resulting from an explicit\nbind() and those implicitly bound through autobind during connect().\n\nPrevents socket unbinding during a transport reassignment, which fixes a\nuse-after-free:\n\n    1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\n    2. transport-\u003erelease() calls vsock_remove_bound() without checking if\n       sk was bound and moved to bound list (refcnt=1)\n    3. vsock_bind() assumes sk is in unbound list and before\n       __vsock_insert_bound(vsock_bound_sockets()) calls\n       __vsock_remove_bound() which does:\n           list_del_init(\u0026vsk-\u003ebound_table); // nop\n           sock_put(\u0026vsk-\u003esk);               // refcnt=0\n\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n __vsock_bind+0x62e/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAllocated by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n __vsock_create.constprop.0+0x2e/0xb60\n vsock_create+0xe4/0x420\n __sock_create+0x241/0x650\n __sys_socket+0xf2/0x1a0\n __x64_sys_socket+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n __vsock_bind+0x5e1/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\nRIP: 0010:refcount_warn_saturate+0xce/0x150\n __vsock_bind+0x66d/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\nRIP: 0010:refcount_warn_saturate+0xee/0x150\n vsock_remove_bound+0x187/0x1e0\n __vsock_release+0x383/0x4a0\n vsock_release+0x90/0x120\n __sock_release+0xa3/0x250\n sock_close+0x14/0x20\n __fput+0x359/0xa80\n task_work_run+0x107/0x1d0\n do_exit+0x847/0x2560\n do_group_exit+0xb8/0x250\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0xfec/0x14f0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e"
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173"
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        {
          "url": "https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c"
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          "url": "https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a"
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    "cveId": "CVE-2025-21756",
    "datePublished": "2025-02-27T02:18:11.547Z",
    "dateReserved": "2024-12-29T08:45:45.760Z",
    "dateUpdated": "2025-11-03T19:37:01.186Z",
    "state": "PUBLISHED"
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  "vulnerability-lookup:meta": {
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[{\"Exploitation\": \"poc\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-08-14T21:01:56.187542Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-416\", \"description\": \"CWE-416 Use After Free\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-02-27T18:14:20.000Z\"}}], \"cna\": {\"title\": \"vsock: Keep the binding until socket destruction\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"e7754d564579a5db9c5c9f74228df5d6dd6f1173\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"e48fcb403c2d0e574c19683f09399ab4cf67809c\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"42b33381e5e1f2b967dc4fb4221ddb9aaf10d197\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"3f43540166128951cc1be7ab1ce6b7f05c670d8b\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"645ce25aa0e67895b11d89f27bb86c9d444c40f8\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"b1afd40321f1c243cffbcf40ea7ca41aca87fa5e\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c0cfa2d8a788fcf45df5bf4070ab2474c88d543a\", \"lessThan\": \"fcdd2242c0231032fc84e1404315c245ae56322a\", \"versionType\": \"git\"}], \"programFiles\": [\"net/vmw_vsock/af_vsock.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.5\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.5\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.10.235\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15.179\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.131\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.79\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.16\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.13.4\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.13.*\"}, {\"status\": \"unaffected\", \"version\": \"6.14\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"net/vmw_vsock/af_vsock.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173\"}, {\"url\": \"https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c\"}, {\"url\": \"https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197\"}, {\"url\": \"https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b\"}, {\"url\": \"https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8\"}, {\"url\": \"https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e\"}, {\"url\": \"https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nvsock: Keep the binding until socket destruction\\n\\nPreserve sockets bindings; this includes both resulting from an explicit\\nbind() and those implicitly bound through autobind during connect().\\n\\nPrevents socket unbinding during a transport reassignment, which fixes a\\nuse-after-free:\\n\\n    1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\\n    2. transport-\u003erelease() calls vsock_remove_bound() without checking if\\n       sk was bound and moved to bound list (refcnt=1)\\n    3. vsock_bind() assumes sk is in unbound list and before\\n       __vsock_insert_bound(vsock_bound_sockets()) calls\\n       __vsock_remove_bound() which does:\\n           list_del_init(\u0026vsk-\u003ebound_table); // nop\\n           sock_put(\u0026vsk-\u003esk);               // refcnt=0\\n\\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\\n dump_stack_lvl+0x68/0x90\\n print_report+0x174/0x4f6\\n kasan_report+0xb9/0x190\\n __vsock_bind+0x62e/0x730\\n vsock_bind+0x97/0xe0\\n __sys_bind+0x154/0x1f0\\n __x64_sys_bind+0x6e/0xb0\\n do_syscall_64+0x93/0x1b0\\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\\n\\nAllocated by task 2057:\\n kasan_save_stack+0x1e/0x40\\n kasan_save_track+0x10/0x30\\n __kasan_slab_alloc+0x85/0x90\\n kmem_cache_alloc_noprof+0x131/0x450\\n sk_prot_alloc+0x5b/0x220\\n sk_alloc+0x2c/0x870\\n __vsock_create.constprop.0+0x2e/0xb60\\n vsock_create+0xe4/0x420\\n __sock_create+0x241/0x650\\n __sys_socket+0xf2/0x1a0\\n __x64_sys_socket+0x6e/0xb0\\n do_syscall_64+0x93/0x1b0\\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\\n\\nFreed by task 2057:\\n kasan_save_stack+0x1e/0x40\\n kasan_save_track+0x10/0x30\\n kasan_save_free_info+0x37/0x60\\n __kasan_slab_free+0x4b/0x70\\n kmem_cache_free+0x1a1/0x590\\n __sk_destruct+0x388/0x5a0\\n __vsock_bind+0x5e1/0x730\\n vsock_bind+0x97/0xe0\\n __sys_bind+0x154/0x1f0\\n __x64_sys_bind+0x6e/0xb0\\n do_syscall_64+0x93/0x1b0\\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\\n\\nrefcount_t: addition on 0; use-after-free.\\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\\nRIP: 0010:refcount_warn_saturate+0xce/0x150\\n __vsock_bind+0x66d/0x730\\n vsock_bind+0x97/0xe0\\n __sys_bind+0x154/0x1f0\\n __x64_sys_bind+0x6e/0xb0\\n do_syscall_64+0x93/0x1b0\\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\\n\\nrefcount_t: underflow; use-after-free.\\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\\nRIP: 0010:refcount_warn_saturate+0xee/0x150\\n vsock_remove_bound+0x187/0x1e0\\n __vsock_release+0x383/0x4a0\\n vsock_release+0x90/0x120\\n __sock_release+0xa3/0x250\\n sock_close+0x14/0x20\\n __fput+0x359/0xa80\\n task_work_run+0x107/0x1d0\\n do_exit+0x847/0x2560\\n do_group_exit+0xb8/0x250\\n __x64_sys_exit_group+0x3a/0x50\\n x64_sys_call+0xfec/0x14f0\\n do_syscall_64+0x93/0x1b0\\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.235\", \"versionStartIncluding\": \"5.5\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.179\", \"versionStartIncluding\": \"5.5\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.131\", \"versionStartIncluding\": \"5.5\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.79\", \"versionStartIncluding\": \"5.5\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.16\", \"versionStartIncluding\": \"5.5\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.13.4\", \"versionStartIncluding\": \"5.5\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.14\", \"versionStartIncluding\": \"5.5\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-05-04T07:20:28.873Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-21756\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-11-03T19:37:01.186Z\", \"dateReserved\": \"2024-12-29T08:45:45.760Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-02-27T02:18:11.547Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.