Anthropic describes a Linux Multipath TCP handshake race leading from an information leak to a kernel use-after-free and a controlled root-command exploit. The attack depends on an affected kernel and an MPTCP listener reachable by the attacker; it is not a generic TCP remote-root issue. Researchers report a roughly 48-minute leak stage followed by a…
Inspect the ClaimsCase · DiggingBeagle record
Claude-assisted Linux MPTCP race led to remote root execution in a controlled test
Anthropic describes a Linux Multipath TCP handshake race leading from an information leak to a kernel use-after-free and a controlled root-command exploit. Researchers report a roughly 48-minute leak stage followed by a further exploit stage in the test configuration.
Scope
The attack depends on an affected kernel and an MPTCP listener reachable by the attacker; it is not a generic TCP remote-root issue. The timing and reliability are environment-specific and no in-the-wild attack or population prevalence was established.
Assessment profile
Assessment method- Setting
- research demonstration
- Exploitation
- demonstrated
- Evidence
- Grade B
- Remediation
- fixed reported
- AI role
- WITH AI
Basis and provenance
The cited primary technical report or advisory supports the stated mechanism within its reported scope. The assessment does not infer a production breach, a victim count or a comparable impact score from a laboratory result. The vendor reports that the affected product was repaired; independent regression reproduction was not performed. Boundary: The kernel address disclosure and subsequent control-flow stage are separate prerequisites.
Assessed Oct 29, 2026 using diggingbeagle.assessment/1.
Evidence basis: CLM-CP23-ANTHROPIC-LINUX-MPTCP-ROOT-1 · CLM-ENRICH-20261029-03 · Anthropic Frontier Red Team: five disclosed model-assisted exploit chains
At a glance
Researchers report a roughly 48-minute leak stage followed by a further exploit stage in the test configuration.
Read the implicationsThe timing and reliability are environment-specific and no in-the-wild attack or population prevalence was established.
Limits and uncertaintyFull account
Anthropic describes a Linux Multipath TCP handshake race leading from an information leak to a kernel use-after-free and a controlled root-command exploit.
The attack depends on an affected kernel and an MPTCP listener reachable by the attacker; it is not a generic TCP remote-root issue. Researchers report a roughly 48-minute leak stage followed by a further exploit stage in the test configuration.
The timing and reliability are environment-specific and no in-the-wild attack or population prevalence was established. Apply the backported kernel patch and verify that exposed MPTCP listeners are covered.
Evidence interpretation and control boundary. The kernel address disclosure and subsequent control-flow stage are separate prerequisites. A system must offer the vulnerable Multipath TCP functionality to an attacker before this remote path matters, and the reported multi-minute leak-and-race timing belongs to the reproduced configuration rather than to all Linux machines. A kernel update is stronger evidence of remediation than simply disabling a high-level AI integration.
Mechanism and trust boundary
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Timeline
- Oct 27, 2026disclosure
Public disclosure
Claims & evidence
CLM-ENRICH-20261029-03Anthropic reports a research-chain Linux MPTCP kernel exploit that first leaks kernel information and subsequently reaches a root command in controlled conditions; the report does not document live compromise of arbitrary Linux hosts.supported
Basis: reported finding
- supportsAnthropic Frontier Red Team: five disclosed model-assisted exploit chainsprimary disclosure
Anthropic report: Chapter 5, Linux MPTCP zero-click exploit chain and CVE-2026-98432
CLM-CP23-ANTHROPIC-LINUX-MPTCP-ROOT-1Anthropic describes a Linux Multipath TCP handshake race leading from an information leak to a kernel use-after-free and a controlled root-command exploit. The attack depends on an affected kernel and an MPTCP listener reachable by the attacker; it is not a generic TCP remote-root issue. Researchers report a roughly 48-minute leak stage followed by a further exploit stage in the test configuration.supported
Basis: reported finding
- supportsAnthropic Frontier Red Team: five disclosed model-assisted exploit chainsprimary disclosure
Anthropic report: Chapter 5, Linux MPTCP zero-click exploit chain and CVE-2026-98432
Implications
Researchers report a roughly 48-minute leak stage followed by a further exploit stage in the test configuration.
Controls and mitigations
- Apply the backported kernel patch and verify that exposed MPTCP listeners are covered.
Unknowns and contradictions
- The timing and reliability are environment-specific and no in-the-wild attack or population prevalence was established.
Sources and citation
Material revision history
- Oct 29, 2026 · Canonical change recorded · new in release · revision 202