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NVD / CVE Program· CNA Linux

CVE-2025-21947: ksmbd: fix type confusion via race condition when using ipc_msg_send_request

Noroxi assessment

Priority: Monitor (action score 18/100)

  • 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: 0.39% (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 1e8833c03a38e1d5d5df6484e3f670a2fd38fb76, 3cb2b2e41541fe6f9cc55ca22d4c0bd260498aea, 6321bbda4244b93802d61cfe0887883aae322f4b; azl3 kernel 6.6.82.1-1 on Azure Linux 3.0 6.6.85.1-2; azl3 kernel 6.6.85.1-2 on Azure Linux 3.0 6.6.85.1-2.
  • Severity is disputed: the assigning authority (CNA) scores it 8.1, NVD 4.7.

Low priority for now. Upgrade to Linux Linux 1e8833c03a38e1d5d5df6484e3f670a2fd38fb76, 3cb2b2e41541fe6f9cc55ca22d4c0bd260498aea, 6321bbda4244b93802d61cfe0887883aae322f4b; azl3 kernel 6.6.82.1-1 on Azure Linux 3.0 6.6.85.1-2; azl3 kernel 6.6.85.1-2 on Azure Linux 3.0 6.6.85.1-2 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 type confusion via race condition when using ipc_msg_send_request req->handle is allocated using ksmbd_acquire_id(&ipc_ida), based on ida_alloc. req->handle from ksmbd_ipc_login_request and FSCTL_PIPE_TRANSCEIVE ioctl can be same and it could lead to type confusion between messages, resulting in access to unexpected parts of memory after an incorrect delivery. ksmbd check type of ipc response but missing add continue to check next ipc reponse.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Apr 1, 2025
Updated
Aug 5, 2026
EPSS
0.3% · 33th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
4.7
CNA · Linux
8.1
3.4 point gap

CVSS:3.1/AV:N/AC:H/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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-21947

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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 kernel5.15 and later · before 6.1.131
  • linux linux kernel6.2 and later · before 6.6.83
  • linux linux kernel6.7 and later · before 6.12.19
  • linux linux kernel6.13 and later · before 6.13.7
  • linux linux kernel6.14

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

    • 5.15affected
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 6321bbda4244b93802d61cfe0887883aae322f4baffected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 76861630b29e51373e73e7b00ad0d467b6941162affected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 3cb2b2e41541fe6f9cc55ca22d4c0bd260498aeaaffected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 1e8833c03a38e1d5d5df6484e3f670a2fd38fb76affected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before e2ff19f0b7a30e03516e6eb73b948e27a55bc9d2affected · git
    • before 5.15not affected · semver
    • 6.1.131 and later · up to and including 6.1.*not affected · semver
    • 6.6.83 and later · up to and including 6.6.*not affected · semver
    • 6.12.19 and later · up to and including 6.12.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.133-16.1.133-1
Debian:13linuxbefore 6.12.19-16.12.19-1

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-2025-21945Apr 1, 2025 · ksmbd: fix use-after-free in smb2_lock
    31Monitor
  • ← EarlierCVE-2025-21946Apr 1, 2025 · ksmbd: fix out-of-bounds in parse_sec_desc()
    28Monitor
  • Later →CVE-2025-21948Apr 1, 2025 · HID: appleir: Fix potential NULL dereference at raw event handle
    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 Linux1e8833c03a38e1d5d5df6484e3f670a2fd38fb76Vendor (CNA)
Linux Linux3cb2b2e41541fe6f9cc55ca22d4c0bd260498aeaVendor (CNA)
Linux Linux6321bbda4244b93802d61cfe0887883aae322f4bVendor (CNA)
Linux Linux76861630b29e51373e73e7b00ad0d467b6941162Vendor (CNA)
Linux Linuxe2ff19f0b7a30e03516e6eb73b948e27a55bc9d2Vendor (CNA)
azl3 kernel 6.6.82.1-1 on Azure Linux 3.06.6.85.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.85.1-2 on Azure Linux 3.06.6.85.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.133-1 · Debian:12Package 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
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
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:N/I:N/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 (5 more)

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

All records