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NVD / CVE Program· CNA Linux

CVE-2025-21844: smb: client: Add check for next_buffer in receive_encrypted_standard()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.61% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 24e8e4523d3071bc5143b0db9127d511489f7b3b, 5.10.235, 5.15.179; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.82.1-1; azl3 kernel 6.6.82.1-1 on Azure Linux 3.0 6.6.82.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 7.5, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 24e8e4523d3071bc5143b0db9127d511489f7b3b, 5.10.235, 5.15.179; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.82.1-1; azl3 kernel 6.6.82.1-1 on Azure Linux 3.0 6.6.82.1-1 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: smb: client: Add check for next_buffer in receive_encrypted_standard() Add check for the return value of cifs_buf_get() and cifs_small_buf_get() in receive_encrypted_standard() to prevent null pointer dereference.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Mar 12, 2025
Updated
Oct 15, 2026
EPSS
0.6% · 49th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
7.5
2.0 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2025-21844

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 kernel6.1.69 and later · before 6.1.130
  • linux linux kernel6.6.8 and later · before 6.6.80
  • linux linux kernel6.7 and later · before 6.12.17
  • linux linux kernel6.13 and later · before 6.13.5
  • linux linux kernel5.10.211
  • linux linux kernel5.15.150
  • 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

    • 6.7affected
    • b03c8099a738a04d2343547ae6a04e5f0f63d3fa and later · before f277e479eea3d1aa18bc712abe1d2bf3dece2e30affected · git
    • 858e73ff25639a0cc1f6f8d2587b62c045867e41 and later · before f618aeb6cad2307e48a641379db610abcf593edfaffected · git
    • 9f528a8e68327117837b5e28b096f52af4c26a05 and later · before 24e8e4523d3071bc5143b0db9127d511489f7b3baffected · git
    • 534733397da26de0303057ce0b93a22bda150365 and later · before 9e5d99a4cf2e23c716b44862975548415fae5391affected · git
    • eec04ea119691e65227a97ce53c0da6b9b74b0b7 and later · before a9b0b4b29877cb4dc5d0842b59b5ccbacddb85bdaffected · git
    • eec04ea119691e65227a97ce53c0da6b9b74b0b7 and later · before 554736b583f529ee159aa95af9a0cbc12b5ffc96affected · git
    • eec04ea119691e65227a97ce53c0da6b9b74b0b7 and later · before 860ca5e50f73c2a1cef7eefc9d39d04e275417f7affected · git
    • 5.10.211 and later · before 5.10.235affected · semver
    • 5.15.150 and later · before 5.15.179affected · 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 6.12.17-16.12.17-1

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-2025-21860Mar 12, 2025 · mm/zswap: fix inconsistency when zswap_store_page() fails
    13Monitor
  • ← EarlierCVE-2025-21866Mar 12, 2025 · powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC
    22Monitor
  • Later →CVE-2025-21846Mar 12, 2025 · acct: perform last write from workqueue
    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 Linux24e8e4523d3071bc5143b0db9127d511489f7b3bVendor (CNA)
Linux Linux5.10.235Vendor (CNA)
Linux Linux5.15.179Vendor (CNA)
Linux Linux554736b583f529ee159aa95af9a0cbc12b5ffc96Vendor (CNA)
Linux Linux6.1.130Vendor (CNA)
Linux Linux6.6.80Vendor (CNA)
Linux Linux860ca5e50f73c2a1cef7eefc9d39d04e275417f7Vendor (CNA)
Linux Linux9e5d99a4cf2e23c716b44862975548415fae5391Vendor (CNA)
Linux Linuxa9b0b4b29877cb4dc5d0842b59b5ccbacddb85bdVendor (CNA)
Linux Linuxf277e479eea3d1aa18bc712abe1d2bf3dece2e30Vendor (CNA)
Linux Linuxf618aeb6cad2307e48a641379db610abcf593edfVendor (CNA)
azl3 kernel 6.6.78.1-3 on Azure Linux 3.06.6.82.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.82.1-1 on Azure Linux 3.06.6.82.1-1 · 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.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/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.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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

References

Show all references (10 more)

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

All records