CVE-2025-38181Network attack vector

Remote kernel crash via CALIPSO SYN cookies

Published Jul 4, 2025 · Updated Aug 5, 2026

NULL pointer dereference in Linux allows remote attackers to crash the kernel through CALIPSO IPv6 SYN-cookie handling. calipso_req_setattr() passes a NULL socket returned by sk_to_full_sk() to sock_omalloc() when a cookie request lacks rsk_listener. Reachability requires an IPv6 TCP listener with a CALIPSO NetLabel mapping and active SYN cookies, which a SYN flood can induce under the default setting.

CVSS severity7.5
High
EPSS probability0.48%
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 allows remote attackers to crash the kernel through CALIPSO IPv6 SYN-cookie handling. calipso_req_setattr() passes a NULL socket returned by sk_to_full_sk() to sock_omalloc() when a cookie request lacks rsk_listener. Reachability requires an IPv6 TCP listener with a CALIPSO NetLabel mapping and active SYN cookies, which a SYN flood can induce under the default setting.

The record

CVE
CVE-2025-38181
Published
Jul 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=4.8
  2. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <058dd4a370f23a5553a9449f2db53d5bfa88d45e
  3. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <10876da918fa1aec0227fb4c67647513447f53a9
  4. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <956f1499412ed0953f6a116df7fdb855e9f1fc66
  5. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <988edde4d52d5c02ea4dd95d7619372a5e2fb7b7
  6. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <bde8833eb075ba8e8674de88e32de6b669966451
  7. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <d092c7fd8e220b23d6c47e03d7d0cc79e731f379
  8. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <dc724bd34d56f5589f7587a091a8cda2386826c4
  9. Affected versionversion=e1adea927080821ebfa7505bff752a4015955660 <f4ae0f61dd9a63329ecb49b1e6356139d43240b8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.8; version=e1adea927080821ebfa7505bff752a4015955660 <058dd4a370f23a5553a9449f2db53d5bfa88d45e; version=e1adea927080821ebfa7505bff752a4015955660 <10876da918fa1aec0227fb4c67647513447f53a9; version=e1adea927080821ebfa7505bff752a4015955660 <956f1499412ed0953f6a116df7fdb855e9f1fc66; version=e1adea927080821ebfa7505bff752a4015955660 <988edde4d52d5c02ea4dd95d7619372a5e2fb7b7; version=e1adea927080821ebfa7505bff752a4015955660 <bde8833eb075ba8e8674de88e32de6b669966451; version=e1adea927080821ebfa7505bff752a4015955660 <d092c7fd8e220b23d6c47e03d7d0cc79e731f379; version=e1adea927080821ebfa7505bff752a4015955660 <dc724bd34d56f5589f7587a091a8cda2386826c4; version=e1adea927080821ebfa7505bff752a4015955660 <f4ae0f61dd9a63329ecb49b1e6356139d43240b8

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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