CVE-2025-68291

Kernel oops via uninitialized MPTCP receive MSS

Published Dec 16, 2025 · Updated Dec 16, 2025

Divide-by-zero in the Linux kernel MPTCP subsystem allows local users to trigger a kernel oops through an MPTCP fast-close path. The mptcp_do_fastclose() function calls tcp_send_active_reset() before initializing rcv_mss, leaving __tcp_select_window() to divide by zero while building the reset. Triggering the flaw requires local access to drive an MPTCP socket through disconnect and fast-open send handling; the demonstrated consequence is a kernel oops and service interruption.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide-by-zero in the Linux kernel MPTCP subsystem allows local users to trigger a kernel oops through an MPTCP fast-close path. The mptcp_do_fastclose() function calls tcp_send_active_reset() before initializing rcv_mss, leaving __tcp_select_window() to divide by zero while building the reset. Triggering the flaw requires local access to drive an MPTCP socket through disconnect and fast-open send handling; the demonstrated consequence is a kernel oops and service interruption.

The record

CVE
CVE-2025-68291
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 2025Record 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=3a13454fd098ed51e733958488f8ec62859a9ed8
  2. Affected versionversion=6.12.60 <6.12.61
  3. Affected versionversion=6.17.10 <6.17.11
  4. Affected versionversion=9ea05fabce31ff93a0adae8221c58bc6d7b832f3
  5. Affected versionversion=ae155060247be8dcae3802a95bd1bdf93ab3215d <f07f4ea53e22429c84b20832fa098b5ecc0d4e35
  6. Affected versionversion=c4f7b0916b95fd2226e5ab98882482b08f52e1c0 <88163f85d59b4164884df900ee171720fd26686b
  7. Affected versionversion=f6fb2cbc91a81178dea23d463503b4525a76825d <05f5e26d488cdc7abc2a826cf1071782d5a21203

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3a13454fd098ed51e733958488f8ec62859a9ed8; version=6.12.60 <6.12.61; version=6.17.10 <6.17.11; version=9ea05fabce31ff93a0adae8221c58bc6d7b832f3; version=ae155060247be8dcae3802a95bd1bdf93ab3215d <f07f4ea53e22429c84b20832fa098b5ecc0d4e35; version=c4f7b0916b95fd2226e5ab98882482b08f52e1c0 <88163f85d59b4164884df900ee171720fd26686b; version=f6fb2cbc91a81178dea23d463503b4525a76825d <05f5e26d488cdc7abc2a826cf1071782d5a21203

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/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.

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No observations available

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

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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