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  4. CVE 2025 21844 smb client add check for nextbuffer in
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Back to active CVEs
High · CVSS 7.5CVE-2025-21844

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

Answer in brief

CVE-2025-21844 records a High severity (CVSS 7.5) vulnerability in smb: client: Add check for next_buffer in receive_encrypted_standard(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Mar 12, 2025Updated Oct 15, 2026Source checked Nov 5, 2026First seen by HOL Aug 5, 2026Material review Oct 15, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 7.5
Exploitation
Not marked as known exploited
Affected software
9 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:5.10.211:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:5.15.150:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Linux/Linuxgeneric>=b03c8099a738a04d2343547ae6a04e5f0f63d3fa <f277e479eea3d1aa18bc712abe1d2bf3dece2e30 || >=858e73ff25639a0cc1f6f8d2587b62c045867e41 <f618aeb6cad2307e48a641379db610abcf593edf || >=9f528a8e68327117837b5e28b096f52af4c26a05 <24e8e4523d3071bc5143b0db9127d511489f7b3b || >=534733397da26de0303057ce0b93a22bda150365 <9e5d99a4cf2e23c716b44862975548415fae5391 || >=eec04ea119691e65227a97ce53c0da6b9b74b0b7 <a9b0b4b29877cb4dc5d0842b59b5ccbacddb85bd || >=eec04ea119691e65227a97ce53c0da6b9b74b0b7 <554736b583f529ee159aa95af9a0cbc12b5ffc96 || >=eec04ea119691e65227a97ce53c0da6b9b74b0b7 <860ca5e50f73c2a1cef7eefc9d39d04e275417f7 || >=5.10.211 <5.10.235 || >=5.15.150 <5.15.179 || >=6.1.69 <6.1.130 || >=6.6.8 <6.6.80f277e479eea3d1aa18bc712abe1d2bf3dece2e30, f618aeb6cad2307e48a641379db610abcf593edf, 24e8e4523d3071bc5143b0db9127d511489f7b3b, 9e5d99a4cf2e23c716b44862975548415fae5391, a9b0b4b29877cb4dc5d0842b59b5ccbacddb85bd, 554736b583f529ee159aa95af9a0cbc12b5ffc96, 860ca5e50f73c2a1cef7eefc9d39d04e275417f7, 5.10.235, 5.15.179, 6.1.130, 6.6.80
Linux/Linuxgeneric6.7Not reported
Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric>=0 <**

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux, Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem.
  2. 2Review the reported fix. Update Linux/Linux to f277e479eea3d1aa18bc712abe1d2bf3dece2e30; Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to * if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Mar 12, 2025

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 15, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Aug 5, 2026

Sources and claim methodology

  • Source referencecert-portal.siemens.com
  • Source referencecert-portal.siemens.com
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencelists.debian.org
  • Source referencelists.debian.org
Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-476
Source
CVE List V5
Source checked
Nov 5, 2026
References
11 linked sources
Open source record