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CVE Record

CVE-2022-50070: mptcp: do not queue data on closed subflows

In the Linux kernel, the following vulnerability has been resolved: mptcp: do not queue data on closed subflows Dipanjan reported a syzbot splat at close time: WARNING: CPU: 1 PID: 10818 at net/ipv4/af_inet.c:153 inet_sock_destruct+0x6d0/0x8e0 net/ipv4/af_inet.c:153 Modules linked in: uio_ivshmem(OE) uio(E) CPU: 1 PID: 10818 Comm: kworker/1:16 Tainted: G OE 5.19.0-rc6-g2eae0556bb9d #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:inet_sock_destruct+0x6d0/0x8e0 net/ipv4/af_inet.c:153 Code: 21 02 00 00 41 8b 9c 24 28 02 00 00 e9 07 ff ff ff e8 34 4d 91 f9 89 ee 4c 89 e7 e8 4a 47 60 ff e9 a6 fc ff ff e8 20 4d 91 f9 <0f> 0b e9 84 fe ff ff e8 14 4d 91 f9 0f 0b e9 d4 fd ff ff e8 08 4d RSP: 0018:ffffc9001b35fa78 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000002879d0 RCX: ffff8881326f3b00 RDX: 0000000000000000 RSI: ffff8881326f3b00 RDI: 0000000000000002 RBP: ffff888179662674 R08: ffffffff87e983a0 R09: 0000000000000000 R10: 0000000000000005 R11: 00000000000004ea R12: ffff888179662400 R13: ffff888179662428 R14: 0000000000000001 R15: ffff88817e38e258 FS: 0000000000000000(0000) GS:ffff8881f5f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020007bc0 CR3: 0000000179592000 CR4: 0000000000150ee0 Call Trace: <TASK> __sk_destruct+0x4f/0x8e0 net/core/sock.c:2067 sk_destruct+0xbd/0xe0 net/core/sock.c:2112 __sk_free+0xef/0x3d0 net/core/sock.c:2123 sk_free+0x78/0xa0 net/core/sock.c:2134 sock_put include/net/sock.h:1927 [inline] __mptcp_close_ssk+0x50f/0x780 net/mptcp/protocol.c:2351 __mptcp_destroy_sock+0x332/0x760 net/mptcp/protocol.c:2828 mptcp_worker+0x5d2/0xc90 net/mptcp/protocol.c:2586 process_one_work+0x9cc/0x1650 kernel/workqueue.c:2289 worker_thread+0x623/0x1070 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> The root cause of the problem is that an mptcp-level (re)transmit can race with mptcp_close() and the packet scheduler checks the subflow state before acquiring the socket lock: we can try to (re)transmit on an already closed ssk. Fix the issue checking again the subflow socket status under the subflow socket lock protection. Additionally add the missing check for the fallback-to-tcp case.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2022-50070 is a Linux kernel MPTCP race condition. During socket close, retransmission could target a subflow that was already closed, triggering a kernel warning. The supplied sources do not provide CVSS, confirmed impact beyond the warning, or evidence of exploitation.

Executive priority

Track as a kernel reliability risk with incomplete severity data. Prioritize remediation through normal kernel maintenance, escalating for internet-facing or high-availability systems using MPTCP.

Technical view

The MPTCP packet scheduler checked subflow state before taking the subflow socket lock. A concurrent mptcp_close() could close the subflow before retransmission, causing data to be queued on a closed socket. The kernel fix rechecks socket status under lock and adds a missing fallback-to-TCP check.

Likely exposure

Exposure is limited to Linux systems running affected kernel builds with MPTCP code reachable. The source metadata lists Linux kernel versions including 5.10, 5.15.190, 5.19.4, and 6.0, but distribution backports may change practical exposure.

Exploitation context

The source bundle cites a syzbot-reported kernel warning and marks KEV as false. No supplied source confirms active exploitation, exploit availability, privilege requirements, or a remote attack path.

Researcher notes

Evidence supports a concurrency bug in MPTCP close and retransmit handling. The public record does not establish confidentiality, integrity, or code-execution impact. Validation should focus on kernel lineage, MPTCP enablement, and whether vendor patches include the cited locking fix.

Mitigation direction

  • Check vendor kernel advisories for CVE-2022-50070 applicability.
  • Update to a kernel containing the referenced stable fixes.
  • Confirm distribution backports rather than relying only on upstream version numbers.
  • If MPTCP is unused, review vendor guidance on disabling or limiting it.

Validation and detection

  • Inventory Linux kernel versions across servers and appliances.
  • Identify systems where MPTCP is enabled or exposed.
  • Compare installed kernels against vendor advisories and stable commit references.
  • Review kernel logs for related MPTCP or inet_sock_destruct warnings.
Prepared
Confidence
medium
Sources
5

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

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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
0ADP providers
4Source links

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

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxd5f49190def61c47b2faff170ba8fbc48bac4371, d5f49190def61c47b2faff170ba8fbc48bac4371, d5f49190def61c47b2faff170ba8fbc48bac4371unaffected
LinuxLinux5.10, 0, 5.15.190, 5.19.4, 6.0affected
Weakness

CWE details

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