{ "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-2025-21756", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-21756", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-02-27T02:18:11.547Z", "updatedAt": "2026-10-15T01:04:00.229Z", "importedAt": "2026-10-24T01:57:29.455Z", "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": "vsock: Keep the binding until socket destruction", "summary": "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->release() 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(&vsk->bound_table); // nop\n sock_put(&vsk->sk); // 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", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "e7754d564579a5db9c5c9f74228df5d6dd6f1173" }, { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "e48fcb403c2d0e574c19683f09399ab4cf67809c" }, { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "42b33381e5e1f2b967dc4fb4221ddb9aaf10d197" }, { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "3f43540166128951cc1be7ab1ce6b7f05c670d8b" }, { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "645ce25aa0e67895b11d89f27bb86c9d444c40f8" }, { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "b1afd40321f1c243cffbcf40ea7ca41aca87fa5e" }, { "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "status": "affected", "versionType": "git", "lessThan": "fcdd2242c0231032fc84e1404315c245ae56322a" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.5" }, { "version": "5.10.235", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.179", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.131", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.79", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.16", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.13.4", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.13.*" }, { "version": "6.14", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }