CVE-2025-38700

Kernel panic via invalid iSER teardown dereference

Published Sep 4, 2025 · Updated May 12, 2026

NULL pointer dereference in Linux and SIMATIC CN 4100 before 5.0 allows local users to crash the system during iSER connection teardown. The libiscsi connection allocator initializes iscsi_conn->dd_data when dd_size is zero after ib_fast_reg_mr allocation fails, so teardown dereferences an invalid pointer. Exploitation requires low-privilege local access and the iSER allocation-failure path; the bounded consequence is a kernel panic and service interruption.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux and SIMATIC CN 4100 before 5.0 allows local users to crash the system during iSER connection teardown. The libiscsi connection allocator initializes iscsi_conn->dd_data when dd_size is zero after ib_fast_reg_mr allocation fails, so teardown dereferences an invalid pointer. Exploitation requires low-privilege local access and the iSER allocation-failure path; the bounded consequence is a kernel panic and service interruption.

The record

CVE
CVE-2025-38700
Published
Sep 4, 2025
Updated
May 12, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 4, 2025CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.27
  2. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <2b242ea14386a510010eabfbfc3ce81a101f3802
  3. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <35782c32528d82aa21f84cb5ceb2abd3526a8159
  4. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <3ea3a256ed81f95ab0f3281a0e234b01a9cae605
  5. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <66a373f50b4249d57f5a88c7be9676f9d5884865
  6. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <9ea6d961566c7d762ed0204b06db05756fdda3b6
  7. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <a145c269dc5380c063a20a0db7e6df2995962e9d
  8. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <a33d42b7fc24fe03f239fbb0880dd5b4b4b97c19
  9. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <f53af99f441ee79599d8df6113a7144d74cf9153
  10. Affected versionversion=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <fd5aad080edb501ab5c84b7623d612d0e3033403

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.27; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <2b242ea14386a510010eabfbfc3ce81a101f3802; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <35782c32528d82aa21f84cb5ceb2abd3526a8159; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <3ea3a256ed81f95ab0f3281a0e234b01a9cae605; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <66a373f50b4249d57f5a88c7be9676f9d5884865; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <9ea6d961566c7d762ed0204b06db05756fdda3b6; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <a145c269dc5380c063a20a0db7e6df2995962e9d; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <a33d42b7fc24fe03f239fbb0880dd5b4b4b97c19; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <f53af99f441ee79599d8df6113a7144d74cf9153; version=5d91e209fb21fb9cc765729d4c6a85a9fb6c9187 <fd5aad080edb501ab5c84b7623d612d0e3033403
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.0Siemens ProductCERTCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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