Local MPTCP disruption via stale address counter
Published Dec 16, 2025 · Updated Dec 16, 2025
Counter-management error in Linux kernel 6.15 allows local users to interrupt MPTCP networking through normal address removal. The WARN_ON_ONCE guard in mptcp_pm_nl_rm_addr is inverted, so the decrement runs only when the address counter is already zero and skips valid removals while it is positive. Low-privileged local access is required, no user interaction is needed, and the reported consequence is limited to availability rather than data disclosure or modification.
Summary
What happened
Counter-management error in Linux kernel 6.15 allows local users to interrupt MPTCP networking through normal address removal. The WARN_ON_ONCE guard in mptcp_pm_nl_rm_addr is inverted, so the decrement runs only when the address counter is already zero and skips valid removals while it is positive. Low-privileged local access is required, no user interaction is needed, and the reported consequence is limited to availability rather than data disclosure or modification.
The record
- CVE
- CVE-2025-68221
- Published
- Dec 16, 2025
- Updated
- Dec 16, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 16, 2025CVE publishedPublication date reported by the CVE source.
- 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?
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- Affected versionversion=6.15
- Affected versionversion=63611391850850bf27f81afb0d0b6d1237a34006 <92e239e36d600002559074994a545fcfac9afd2d
- Affected versionversion=63611391850850bf27f81afb0d0b6d1237a34006 <f7d953c38245c0e9d8e268fb6a9e524602fb44ec
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What is affected?
Published CVSS scores
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Attacks
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Technologies
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Your stack
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