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NVD / CVE Program· CNA Linux

CVE-2024-53186: ksmbd: fix use-after-free in SMB request handling

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.45% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 6.11, 6.11.11, 6.6.64; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1.
  • Severity is disputed: the assigning authority (CNA) scores it 9.8, NVD 7.0.

Low priority for now. Upgrade to Linux Linux 6.11, 6.11.11, 6.6.64; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in SMB request handling A race condition exists between SMB request handling in `ksmbd_conn_handler_loop()` and the freeing of `ksmbd_conn` in the workqueue handler `handle_ksmbd_work()`. This leads to a UAF. - KASAN: slab-use-after-free Read in handle_ksmbd_work - KASAN: slab-use-after-free in rtlock_slowlock_locked This race condition arises as follows: - `ksmbd_conn_handler_loop()` waits for `conn->r_count` to reach zero: `wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);` - Meanwhile, `handle_ksmbd_work()` decrements `conn->r_count` using `atomic_dec_return(&conn->r_count)`, and if it reaches zero, calls `ksmbd_conn_free()`, which frees `conn`. - However, after `handle_ksmbd_work()` decrements `conn->r_count`, it may still access `conn->r_count_q` in the following line: `waitqueue_active(&conn->r_count_q)` or `wake_up(&conn->r_count_q)` This results in a UAF, as `conn` has already been freed. The discovery of this UAF can be referenced in the following PR for syzkaller's support for SMB requests.

HighCVSS 7.0 · v3.1—No exploit Fix available
Published
Dec 27, 2024
Updated
Aug 5, 2026
EPSS
0.4% · 39th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.0
CNA · Linux
9.8
2.8 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.6.55 and later · before 6.6.64
  • linux linux kernel6.10.14 and later · before 6.11
  • linux linux kernel6.11.3 and later · before 6.11.11
  • linux linux kernel6.12 and later · before 6.12.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 9fd3cde4628bcd3549ab95061f2bab74d2ed4f3b, 6.12affected
    • 18f06bacc197d4ac9b518ad1c69999bc3d83e7aa and later · before a96f9eb7add30ba0fafcfe7b7aca090978196800affected · git
    • e9dac92f4482a382e8c0fe1bc243da5fc3526b0c and later · before f20b77f7897e6aab9ce5527e6016ad2be5d70a33affected · git
    • ee426bfb9d09b29987369b897fe9b6485ac2be27 and later · before 96261adb998a3b513468b6ce17dbec76be5507d4affected · git
    • ee426bfb9d09b29987369b897fe9b6485ac2be27 and later · before 9a8c5d89d327ff58e9b2517f8a6afb4181d32c6eaffected · git
    • 6.6.55 and later · before 6.6.64affected · semver
    • 6.11.3 and later · before 6.11.11affected · semver
    • 6.10.14 and later · before 6.11affected · semver
    • before 6.12not affected · semver
    • 6.6.64 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.3-16.12.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2024-53184Dec 27, 2024 · um: ubd: Do not use drvdata in release
    22Monitor
  • ← EarlierCVE-2024-53185Dec 27, 2024 · smb: client: fix NULL ptr deref in crypto_aead_setkey()
    22Monitor
  • Later →CVE-2024-53188Dec 27, 2024 · wifi: ath12k: fix crash when unbinding
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux6.11Vendor (CNA)
Linux Linux6.11.11Vendor (CNA)
Linux Linux6.6.64Vendor (CNA)
Linux Linux96261adb998a3b513468b6ce17dbec76be5507d4Vendor (CNA)
Linux Linux9a8c5d89d327ff58e9b2517f8a6afb4181d32c6eVendor (CNA)
Linux Linuxa96f9eb7add30ba0fafcfe7b7aca090978196800Vendor (CNA)
Linux Linuxf20b77f7897e6aab9ce5527e6016ad2be5d70a33Vendor (CNA)
azl3 kernel 6.6.57.1-7 on Azure Linux 3.06.6.64.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.12.3-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records