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CVE Record

CVE-2024-46771: can: bcm: Remove proc entry when dev is unregistered.

In the Linux kernel, the following vulnerability has been resolved: can: bcm: Remove proc entry when dev is unregistered. syzkaller reported a warning in bcm_connect() below. [0] The repro calls connect() to vxcan1, removes vxcan1, and calls connect() with ifindex == 0. Calling connect() for a BCM socket allocates a proc entry. Then, bcm_sk(sk)->bound is set to 1 to prevent further connect(). However, removing the bound device resets bcm_sk(sk)->bound to 0 in bcm_notify(). The 2nd connect() tries to allocate a proc entry with the same name and sets NULL to bcm_sk(sk)->bcm_proc_read, leaking the original proc entry. Since the proc entry is available only for connect()ed sockets, let's clean up the entry when the bound netdev is unregistered. [0]: proc_dir_entry 'can-bcm/2456' already registered WARNING: CPU: 1 PID: 394 at fs/proc/generic.c:376 proc_register+0x645/0x8f0 fs/proc/generic.c:375 Modules linked in: CPU: 1 PID: 394 Comm: syz-executor403 Not tainted 6.10.0-rc7-g852e42cc2dd4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:proc_register+0x645/0x8f0 fs/proc/generic.c:375 Code: 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 RSP: 0018:ffa0000000cd7c30 EFLAGS: 00010246 RAX: 9e129be1950f0200 RBX: ff1100011b51582c RCX: ff1100011857cd80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 RBP: 0000000000000000 R08: ffd400000000000f R09: ff1100013e78cac0 R10: ffac800000cd7980 R11: ff1100013e12b1f0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ff1100011a99a2ec FS: 00007fbd7086f740(0000) GS:ff1100013fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200071c0 CR3: 0000000118556004 CR4: 0000000000771ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> proc_create_net_single+0x144/0x210 fs/proc/proc_net.c:220 bcm_connect+0x472/0x840 net/can/bcm.c:1673 __sys_connect_file net/socket.c:2049 [inline] __sys_connect+0x5d2/0x690 net/socket.c:2066 __do_sys_connect net/socket.c:2076 [inline] __se_sys_connect net/socket.c:2073 [inline] __x64_sys_connect+0x8f/0x100 net/socket.c:2073 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7fbd708b0e5d Code: 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 RSP: 002b:00007fff8cd33f08 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fbd708b0e5d RDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000040 R09: 0000000000000040 R10: 0000000000000040 R11: 0000000000000246 R12: 00007fff8cd34098 R13: 0000000000401280 R14: 0000000000406de8 R15: 00007fbd70ab9000 </TASK> remove_proc_entry: removing non-empty directory 'net/can-bcm', leaking at least '2456'

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in the Linux CAN Broadcast Manager can leave a stale proc entry after a connected network device is removed. A later connection may collide with that entry, producing a kernel warning and leaking the original entry. The supplied record rates potential impact as high, but does not demonstrate data theft, system takeover, or remote exploitation.

Executive priority

Treat this as a high-priority kernel maintenance issue on affected multi-user, automotive, industrial, or CAN-enabled Linux systems. Schedule normal expedited patching rather than an internet-facing emergency response unless local threat conditions raise urgency. The absence of documented active exploitation lowers immediate crisis pressure, but the high CVSS score warrants timely validation and remediation.

Technical view

The BCM socket tracks a proc entry after connect. Device unregistration resets the socket's bound state without removing that entry. A subsequent connect can attempt the same proc-entry allocation, set the stored pointer to NULL, and leave the original entry behind. The kernel fix removes the proc entry when the bound network device is unregistered.

Likely exposure

Exposure is limited to affected Linux kernels where CAN BCM is available and a local actor can trigger the relevant socket and network-device lifecycle. The CVSS vector requires local access and low privileges; no network-based path is identified. Confirm exact exposure against distribution kernels and backported fixes because the supplied version list is not sufficiently precise for every build.

Exploitation context

The issue was found by syzkaller using a synthetic virtual CAN-device sequence. The supplied record says it is not in CISA KEV and provides no evidence of active exploitation or a public weaponized exploit. Observed behavior is a kernel warning and leaked proc entry; broader confidentiality, integrity, and availability consequences are not demonstrated in the bundle.

Researcher notes

The supplied CVSS 3.1 score is 7.8 with local, low-complexity, low-privilege access and high CIA impacts. However, the technical description directly establishes a duplicate proc registration warning and resource leak only. No CWE is assigned. Researchers should distinguish the rated potential impact from demonstrated behavior and validate branch-specific backports using the referenced kernel commits.

Mitigation direction

  • Update to a vendor-supported kernel containing the applicable upstream stable fix.
  • Check distribution advisories for backported fixes before relying on version numbers alone.
  • Prioritize systems that enable CAN BCM and permit relevant local network-device operations.
  • If patching is delayed, review vendor guidance for supported temporary mitigations.

Validation and detection

  • Inventory kernel versions and distribution package revisions across Linux systems.
  • Confirm whether each kernel contains its branch-specific referenced stable commit or vendor backport.
  • Determine whether CAN BCM functionality is present or used on exposed hosts.
  • Review kernel logs for duplicate can-bcm proc-entry warnings or non-empty directory removal messages.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2024-46771 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
2ADP providers
11Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2024-46771Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828, ffd980f976e7fd666c2e61bf8ab35107efd11828unaffected
LinuxLinux2.6.25, 0, 4.19.322, 5.4.284, 5.10.226, 5.15.167, 6.1.110, 6.6.51, 6.10.10, 6.11affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.