{"id":"CVE-2024-46771","state":"PUBLISHED","title":"can: bcm: Remove proc entry when dev is unregistered.","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: Remove proc entry when dev is unregistered.\n\nsyzkaller reported a warning in bcm_connect() below. [0]\n\nThe repro calls connect() to vxcan1, removes vxcan1, and calls\nconnect() with ifindex == 0.\n\nCalling connect() for a BCM socket allocates a proc entry.\nThen, bcm_sk(sk)->bound is set to 1 to prevent further connect().\n\nHowever, removing the bound device resets bcm_sk(sk)->bound to 0\nin bcm_notify().\n\nThe 2nd connect() tries to allocate a proc entry with the same\nname and sets NULL to bcm_sk(sk)->bcm_proc_read, leaking the\noriginal proc entry.\n\nSince the proc entry is available only for connect()ed sockets,\nlet's clean up the entry when the bound netdev is unregistered.\n\n[0]:\nproc_dir_entry 'can-bcm/2456' already registered\nWARNING: CPU: 1 PID: 394 at fs/proc/generic.c:376 proc_register+0x645/0x8f0 fs/proc/generic.c:375\nModules linked in:\nCPU: 1 PID: 394 Comm: syz-executor403 Not tainted 6.10.0-rc7-g852e42cc2dd4\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\nRIP: 0010:proc_register+0x645/0x8f0 fs/proc/generic.c:375\nCode: 00 00 00 00 00 48 85 ed 0f 85 97 02 00 00 4d 85 f6 0f 85 9f 02 00 00 48 c7 c7 9b cb cf 87 48 89 de 4c 89 fa e8 1c 6f eb fe 90 <0f> 0b 90 90 48 c7 c7 98 37 99 89 e8 cb 7e 22 05 bb 00 00 00 10 48\nRSP: 0018:ffa0000000cd7c30 EFLAGS: 00010246\nRAX: 9e129be1950f0200 RBX: ff1100011b51582c RCX: ff1100011857cd80\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002\nRBP: 0000000000000000 R08: ffd400000000000f R09: ff1100013e78cac0\nR10: ffac800000cd7980 R11: ff1100013e12b1f0 R12: 0000000000000000\nR13: 0000000000000000 R14: 0000000000000000 R15: ff1100011a99a2ec\nFS:  00007fbd7086f740(0000) GS:ff1100013fd00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00000000200071c0 CR3: 0000000118556004 CR4: 0000000000771ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n <TASK>\n proc_create_net_single+0x144/0x210 fs/proc/proc_net.c:220\n bcm_connect+0x472/0x840 net/can/bcm.c:1673\n __sys_connect_file net/socket.c:2049 [inline]\n __sys_connect+0x5d2/0x690 net/socket.c:2066\n __do_sys_connect net/socket.c:2076 [inline]\n __se_sys_connect net/socket.c:2073 [inline]\n __x64_sys_connect+0x8f/0x100 net/socket.c:2073\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xd9/0x1c0 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\nRIP: 0033:0x7fbd708b0e5d\nCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48\nRSP: 002b:00007fff8cd33f08 EFLAGS: 00000246 ORIG_RAX: 000000000000002a\nRAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fbd708b0e5d\nRDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000003\nRBP: 0000000000000000 R08: 0000000000000040 R09: 0000000000000040\nR10: 0000000000000040 R11: 0000000000000246 R12: 00007fff8cd34098\nR13: 0000000000401280 R14: 0000000000406de8 R15: 00007fbd70ab9000\n </TASK>\nremove_proc_entry: removing non-empty directory 'net/can-bcm', leaking at least '2456'","publishedAt":"2024-09-18T07:12:29.363Z","updatedAt":"2026-08-05T11:38:28.890Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"5c680022c4e28ba18ea500f3e29f0428271afa92","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"33ed4ba73caae39f34ab874ba79138badc2c65dd","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"aec92dbebdbec7567d9f56d7c9296a572b8fd849","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"10bfacbd5e8d821011d857bee73310457c9c989a","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"3b39dc2901aa7a679a5ca981a3de9f8d5658afe8","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"4377b79323df62eb5d310354f19b4d130ff58d50","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"abb0a615569ec008e8a93d9f3ab2d5b418ea94d4","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"76fe372ccb81b0c89b6cd2fec26e2f38c958be85","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/bcm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.25","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.25","versionType":"semver"},{"version":"4.19.322","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.284","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.226","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.167","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.110","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.51","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.10.10","status":"unaffected","lessThanOrEqual":"6.10.*","versionType":"semver"},{"version":"6.11","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/bcm.c"]}],"references":["https://git.kernel.org/stable/c/5c680022c4e28ba18ea500f3e29f0428271afa92","https://git.kernel.org/stable/c/33ed4ba73caae39f34ab874ba79138badc2c65dd","https://git.kernel.org/stable/c/aec92dbebdbec7567d9f56d7c9296a572b8fd849","https://git.kernel.org/stable/c/10bfacbd5e8d821011d857bee73310457c9c989a","https://git.kernel.org/stable/c/3b39dc2901aa7a679a5ca981a3de9f8d5658afe8","https://git.kernel.org/stable/c/4377b79323df62eb5d310354f19b4d130ff58d50","https://git.kernel.org/stable/c/abb0a615569ec008e8a93d9f3ab2d5b418ea94d4","https://git.kernel.org/stable/c/76fe372ccb81b0c89b6cd2fec26e2f38c958be85","https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html","https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:07:47.831Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/46xxx/CVE-2024-46771.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-46771","state":"PUBLISHED","datePublished":"2024-09-18T07:12:29.363Z","dateUpdated":"2026-08-05T11:38:28.890Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-09-11T15:12:18.274Z"},"containers":{"cna":{"title":"can: bcm: Remove proc entry when dev is unregistered.","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: Remove proc entry when dev is unregistered.\n\nsyzkaller reported a warning in bcm_connect() below. [0]\n\nThe repro calls connect() to vxcan1, removes vxcan1, and calls\nconnect() with ifindex == 0.\n\nCalling connect() for a BCM socket allocates a proc entry.\nThen, bcm_sk(sk)->bound is set to 1 to prevent further connect().\n\nHowever, removing the bound device resets bcm_sk(sk)->bound to 0\nin bcm_notify().\n\nThe 2nd connect() tries to allocate a proc entry with the same\nname and sets NULL to bcm_sk(sk)->bcm_proc_read, leaking the\noriginal proc entry.\n\nSince the proc entry is available only for connect()ed sockets,\nlet's clean up the entry when the bound netdev is unregistered.\n\n[0]:\nproc_dir_entry 'can-bcm/2456' already registered\nWARNING: CPU: 1 PID: 394 at fs/proc/generic.c:376 proc_register+0x645/0x8f0 fs/proc/generic.c:375\nModules linked in:\nCPU: 1 PID: 394 Comm: syz-executor403 Not tainted 6.10.0-rc7-g852e42cc2dd4\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\nRIP: 0010:proc_register+0x645/0x8f0 fs/proc/generic.c:375\nCode: 00 00 00 00 00 48 85 ed 0f 85 97 02 00 00 4d 85 f6 0f 85 9f 02 00 00 48 c7 c7 9b cb cf 87 48 89 de 4c 89 fa e8 1c 6f eb fe 90 <0f> 0b 90 90 48 c7 c7 98 37 99 89 e8 cb 7e 22 05 bb 00 00 00 10 48\nRSP: 0018:ffa0000000cd7c30 EFLAGS: 00010246\nRAX: 9e129be1950f0200 RBX: ff1100011b51582c RCX: ff1100011857cd80\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002\nRBP: 0000000000000000 R08: ffd400000000000f R09: ff1100013e78cac0\nR10: ffac800000cd7980 R11: ff1100013e12b1f0 R12: 0000000000000000\nR13: 0000000000000000 R14: 0000000000000000 R15: ff1100011a99a2ec\nFS:  00007fbd7086f740(0000) GS:ff1100013fd00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00000000200071c0 CR3: 0000000118556004 CR4: 0000000000771ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n <TASK>\n proc_create_net_single+0x144/0x210 fs/proc/proc_net.c:220\n bcm_connect+0x472/0x840 net/can/bcm.c:1673\n __sys_connect_file net/socket.c:2049 [inline]\n __sys_connect+0x5d2/0x690 net/socket.c:2066\n __do_sys_connect net/socket.c:2076 [inline]\n __se_sys_connect net/socket.c:2073 [inline]\n __x64_sys_connect+0x8f/0x100 net/socket.c:2073\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xd9/0x1c0 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\nRIP: 0033:0x7fbd708b0e5d\nCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48\nRSP: 002b:00007fff8cd33f08 EFLAGS: 00000246 ORIG_RAX: 000000000000002a\nRAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fbd708b0e5d\nRDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000003\nRBP: 0000000000000000 R08: 0000000000000040 R09: 0000000000000040\nR10: 0000000000000040 R11: 0000000000000246 R12: 00007fff8cd34098\nR13: 0000000000401280 R14: 0000000000406de8 R15: 00007fbd70ab9000\n </TASK>\nremove_proc_entry: removing non-empty directory 'net/can-bcm', leaking at least '2456'"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"5c680022c4e28ba18ea500f3e29f0428271afa92","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"33ed4ba73caae39f34ab874ba79138badc2c65dd","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"aec92dbebdbec7567d9f56d7c9296a572b8fd849","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"10bfacbd5e8d821011d857bee73310457c9c989a","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"3b39dc2901aa7a679a5ca981a3de9f8d5658afe8","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"4377b79323df62eb5d310354f19b4d130ff58d50","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"abb0a615569ec008e8a93d9f3ab2d5b418ea94d4","versionType":"git"},{"version":"ffd980f976e7fd666c2e61bf8ab35107efd11828","status":"affected","lessThan":"76fe372ccb81b0c89b6cd2fec26e2f38c958be85","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/bcm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.25","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.25","versionType":"semver"},{"version":"4.19.322","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.284","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.226","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.167","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.110","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.51","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.10.10","status":"unaffected","lessThanOrEqual":"6.10.*","versionType":"semver"},{"version":"6.11","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/bcm.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5c680022c4e28ba18ea500f3e29f0428271afa92"},{"url":"https://git.kernel.org/stable/c/33ed4ba73caae39f34ab874ba79138badc2c65dd"},{"url":"https://git.kernel.org/stable/c/aec92dbebdbec7567d9f56d7c9296a572b8fd849"},{"url":"https://git.kernel.org/stable/c/10bfacbd5e8d821011d857bee73310457c9c989a"},{"url":"https://git.kernel.org/stable/c/3b39dc2901aa7a679a5ca981a3de9f8d5658afe8"},{"url":"https://git.kernel.org/stable/c/4377b79323df62eb5d310354f19b4d130ff58d50"},{"url":"https://git.kernel.org/stable/c/abb0a615569ec008e8a93d9f3ab2d5b418ea94d4"},{"url":"https://git.kernel.org/stable/c/76fe372ccb81b0c89b6cd2fec26e2f38c958be85"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The entire sequence — CAN_BCM socket creation, connect(), removal of the bound netdev via RTNL, a second connect(), close(), and reading /proc/net/can-bcm/<ino> — requires only local syscalls. No remote or adjacent-network input reaches this code.\nAC:L - The attacker performs a deterministic, self-contained sequence (connect → delete the interface they created → connect → close → read the leaked proc file); there is no race and no condition outside the attacker's control.\nPR:L - An ordinary unprivileged user can open a CAN BCM socket (no capability checks in bcm_connect()) and obtain CAP_NET_ADMIN inside a user namespace (`unshare -Urn`) to create and delete the vcan/vxcan device that triggers bcm_notify(); the leaked proc entry is mode 0644 and world-readable.\nUI:N - The attacker drives every step from a single process; no action by another user or administrator is needed.\nS:U - The dangling proc entry and the freed socket are both kernel objects within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The orphaned procfs entry keeps a pointer to a freed struct sock, so reading it makes bcm_proc_show() dereference and walk lists inside a slab object the attacker can re-allocate with controlled content, yielding an attacker-influenced kernel memory read returned to userspace (plus %pK pointer disclosure).\nI:H - The dangling reference is a use-after-free on a freed socket whose slab can be sprayed with attacker-controlled data; the resulting corrupted-object dereferences and list traversals are the standard basis for control-flow/heap manipulation primitives.\nA:H - The second connect() triggers a proc_register() WARN (fatal with panic_on_warn), and any later read of the leaked entry dereferences freed memory, causing an oops or an endless loop over corrupted list pointers, plus permanent procfs/netns resource leakage."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:38:28.890Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"4.19.322"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"5.4.284"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"5.10.226"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"5.15.167"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.1.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.6.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.10.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2024-09-29T14:40:41.261064Z","id":"CVE-2024-46771","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-09-29T14:40:55.797Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"url":"https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T22:18:13.468Z"}}]}}}