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CVE Record

CVE-2024-35840: mptcp: use OPTION_MPTCP_MPJ_SYNACK in subflow_finish_connect()

In the Linux kernel, the following vulnerability has been resolved: mptcp: use OPTION_MPTCP_MPJ_SYNACK in subflow_finish_connect() subflow_finish_connect() uses four fields (backup, join_id, thmac, none) that may contain garbage unless OPTION_MPTCP_MPJ_SYNACK has been set in mptcp_parse_option()

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2024-35840 is a Linux kernel MPTCP issue where the kernel could read uninitialized option fields during subflow connection handling. Public sources do not provide a CVSS score, business impact, or evidence of active exploitation. Treat this as a kernel hygiene issue, with higher attention for systems using Multipath TCP.

Executive priority

Do not treat this as confirmed emergency exploitation based on current sources. Assign priority to kernel patch management, with elevated focus for network infrastructure or workloads using MPTCP. Track vendor advisories because public severity and impact details are incomplete.

Technical view

In Linux MPTCP, subflow_finish_connect() used backup, join_id, thmac, and none fields that may contain garbage unless mptcp_parse_option() set OPTION_MPTCP_MPJ_SYNACK. Stable kernel commits change this handling. The public record does not specify a CWE, CVSS vector, or concrete security impact.

Likely exposure

Exposure is limited to Linux systems running affected kernel builds with MPTCP code present, especially where Multipath TCP is enabled or used. The source bundle lists Linux as affected and references version markers including 5.7, 5.15.148, 6.1.75, 6.6.14, 6.7.2, and 6.8; validate distro mappings.

Exploitation context

The CVE is not listed as KEV in the provided data, and no cited source reports active exploitation. Public sources do not describe attacker prerequisites, exploitability, or impact beyond incorrect use of potentially uninitialized MPTCP option fields.

Researcher notes

The core evidence is the upstream Linux fix description and stable commits. The record lacks CVSS, CWE, impact analysis, and exploit details. Avoid assuming memory disclosure, crash, or code execution without additional vendor or maintainer analysis.

Mitigation direction

  • Apply Linux kernel updates containing the referenced stable commits.
  • Check your Linux distribution advisory for fixed package versions.
  • Prioritize systems where MPTCP is enabled, exposed, or operationally required.
  • If no vendor package exists, follow vendor kernel-maintenance guidance.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and containers using host kernels.
  • Check whether MPTCP is enabled or used in affected environments.
  • Map installed kernels to distribution advisories and upstream stable commits.
  • Confirm remediation by verifying the running kernel includes the vendor fix.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

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CVE-2024-35840 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf296234c98a8fcec94eec80304a873f635d350ea, f296234c98a8fcec94eec80304a873f635d350ea, f296234c98a8fcec94eec80304a873f635d350ea, f296234c98a8fcec94eec80304a873f635d350ea, f296234c98a8fcec94eec80304a873f635d350eaunaffected
LinuxLinux5.7, 0, 5.15.148, 6.1.75, 6.6.14, 6.7.2, 6.8affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.