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CVE Record

CVE-2023-53217: nubus: Partially revert proc_create_single_data() conversion

In the Linux kernel, the following vulnerability has been resolved: nubus: Partially revert proc_create_single_data() conversion The conversion to proc_create_single_data() introduced a regression whereby reading a file in /proc/bus/nubus results in a seg fault: # grep -r . /proc/bus/nubus/e/ Data read fault at 0x00000020 in Super Data (pc=0x1074c2) BAD KERNEL BUSERR Oops: 00000000 Modules linked in: PC: [<001074c2>] PDE_DATA+0xc/0x16 SR: 2010 SP: 38284958 a2: 01152370 d0: 00000001 d1: 01013000 d2: 01002790 d3: 00000000 d4: 00000001 d5: 0008ce2e a0: 00000000 a1: 00222a40 Process grep (pid: 45, task=142f8727) Frame format=B ssw=074d isc=2008 isb=4e5e daddr=00000020 dobuf=01199e70 baddr=001074c8 dibuf=ffffffff ver=f Stack from 01199e48: 01199e70 00222a58 01002790 00000000 011a3000 01199eb0 015000c0 00000000 00000000 01199ec0 01199ec0 000d551a 011a3000 00000001 00000000 00018000 d003f000 00000003 00000001 0002800d 01052840 01199fa8 c01f8000 00000000 00000029 0b532b80 00000000 00000000 00000029 0b532b80 01199ee4 00103640 011198c0 d003f000 00018000 01199fa8 00000000 011198c0 00000000 01199f4c 000b3344 011198c0 d003f000 00018000 01199fa8 00000000 00018000 011198c0 Call Trace: [<00222a58>] nubus_proc_rsrc_show+0x18/0xa0 [<000d551a>] seq_read+0xc4/0x510 [<00018000>] fp_fcos+0x2/0x82 [<0002800d>] __sys_setreuid+0x115/0x1c6 [<00103640>] proc_reg_read+0x5c/0xb0 [<00018000>] fp_fcos+0x2/0x82 [<000b3344>] __vfs_read+0x2c/0x13c [<00018000>] fp_fcos+0x2/0x82 [<00018000>] fp_fcos+0x2/0x82 [<000b8aa2>] sys_statx+0x60/0x7e [<000b34b6>] vfs_read+0x62/0x12a [<00018000>] fp_fcos+0x2/0x82 [<00018000>] fp_fcos+0x2/0x82 [<000b39c2>] ksys_read+0x48/0xbe [<00018000>] fp_fcos+0x2/0x82 [<000b3a4e>] sys_read+0x16/0x1a [<00018000>] fp_fcos+0x2/0x82 [<00002b84>] syscall+0x8/0xc [<00018000>] fp_fcos+0x2/0x82 [<0000c016>] not_ext+0xa/0x18 Code: 4e5e 4e75 4e56 0000 206e 0008 2068 ffe8 <2068> 0020 2008 4e5e 4e75 4e56 0000 2f0b 206e 0008 2068 0004 2668 0020 206b ffe8 Disabling lock debugging due to kernel taint Segmentation fault The proc_create_single_data() conversion does not work because single_open(file, nubus_proc_rsrc_show, PDE_DATA(inode)) is not equivalent to the original code.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel flaw where reading NuBus proc files can crash the kernel and, based on the CVSS rating, may affect confidentiality, integrity, and availability. It requires local access, so internet exposure is not the main issue. Business urgency depends on whether affected kernels with NuBus proc support exist in your fleet.

Executive priority

Treat as high priority only where affected Linux kernels and local user access coexist. For most modern server fleets, first confirm exposure before emergency action. Patch through normal kernel update channels once applicability is established.

Technical view

A proc_create_single_data() conversion for NuBus changed data handling in /proc/bus/nubus. The source describes a regression where reading a NuBus proc file triggers a kernel bus error and oops because the new single_open/PDE_DATA path is not equivalent to the original code.

Likely exposure

Likely exposure is narrow: Linux systems running affected kernel versions and exposing /proc/bus/nubus NuBus proc entries. The CVSS vector requires local privileges. Standard cloud and server fleets may have low practical exposure unless they run affected kernels with this subsystem enabled.

Exploitation context

The source bundle does not show active exploitation, and KEV is false. Evidence only supports a local, low-complexity trigger involving reading affected proc entries. No remote exploitation evidence is provided.

Researcher notes

The strongest evidence is the kernel regression description and stable commit references. The record does not provide CWE mapping, exploit reports, or detailed affected distribution packages. Avoid assuming broad practical impact without confirming NuBus proc exposure and vendor backport status.

Mitigation direction

  • Apply vendor or distribution kernel updates containing the referenced stable fixes.
  • Check whether your kernel vendor backported the fix before judging by version alone.
  • Limit local user access on systems that expose affected NuBus proc entries.
  • Prioritize remediation for multi-user systems or systems with untrusted local accounts.

Validation and detection

  • Inventory Linux kernel versions against vendor advisories and the CVE record.
  • Confirm whether /proc/bus/nubus is exposed on relevant systems.
  • Verify fixed stable commits or equivalent backports are present in deployed kernels.
  • Review local-access risk on systems with untrusted shell or service accounts.
Prepared
Confidence
medium
Sources
8

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-2023-53217 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
1ADP providers
7Source links

SSVC decision data

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

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:H1.85.9CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2023-53217Attack 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
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux3f3942aca6da351a12543aa776467791b63b3a78, 3f3942aca6da351a12543aa776467791b63b3a78, 3f3942aca6da351a12543aa776467791b63b3a78, 3f3942aca6da351a12543aa776467791b63b3a78, 3f3942aca6da351a12543aa776467791b63b3a78, 3f3942aca6da351a12543aa776467791b63b3a78unaffected
LinuxLinux4.18, 0, 5.10.188, 5.15.120, 6.1.38, 6.3.12, 6.4.2, 6.5affected
Weakness

CWE details

No CWE listed

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