CVE Intelligence
Unknown

CVE-2026-99213 — vsock: treat TCP_CLOSING as once-established

In the Linux kernel, the following vulnerability has been resolved: vsock: treat TCP_CLOSING as once-established Handle the TCP_ESTABLISHED -> TCP_CLOSING transition on OP_RST, which can race with the connect loop. Immediately break and return 0 on ESTABLISHED/CLOSING. The return value of connect() should reflect what happened up to the point the connection was established or failed. Events that occur afterwards must not affect it. E.g. even if OP_RW has already set sk_err, connect() should still return 0, not ENOBUFS because of it. Adapt the inaccurate comment above signal_pending(). Resetting a socket that is still present in connected_table can lead to memory corruption. The reporter noted lost transports for in-flight skbs, and I have reproduced crashes caused by re-insertion into connected_table. list_add double add: new=, prev=, next=. kernel BUG at lib/list_debug.c:35! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI Workqueue: vsock-loopback vsock_loopback_work RIP: 0010:__list_add_valid_or_report+0x11f/0x130 Call Trace: vsock_insert_connected.cold+0xe/0x13 virtio_transport_recv_pkt+0x10e9/0x1460 vsock_loopback_work+0x305/0x480 process_one_work+0xe4c/0x1560 worker_thread+0x4f1/0xd60 kthread+0x36e/0x470 ret_from_fork+0x47b/0x6b0 ret_from_fork_asm+0x1a/0x30 This fix is supplementary to commit 002541ef650b ("vsock: Ignore signal/timeout on connect() if already established"). Details under Link.

Published Oct 28, 2026 · Updated Oct 28, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • No scoring signals.

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ d021c344051af91f42c5ba9fdedc176740cbd238 and < c2c5359ef2c33684fa3f3652fd761a483db8d1e7≥ d021c344051af91f42c5ba9fdedc176740cbd238 and < 44d1ca05d6094a5d75c671a0545249186d790b8d≥ d021c344051af91f42c5ba9fdedc176740cbd238 and < 4f6ac74fa594a918d41255c941256e1d51592d3bversion 3.9 Vulnerable CVE Program (cve.org) e CISA ADP

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 28, 2026
  • Affected products added · linux/linux
    Oct 28, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 28, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 28, 2026 · Alertas do Telegram
  • CVE published
    Oct 28, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 28, 2026 – Oct 28, 2026
  • 1× Official description updated · Oct 28, 2026 – Oct 28, 2026

References

3 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 1h
  • CVE-2026-99214 drm/vc4: hdmi: Move packet RAM enable to PM runtime 1h
  • CVE-2026-99212 net/rds: don't let the rdma_cm destroy an id RDS still owns on route failure 1h
  • CVE-2026-99211 netlink: reset skb headers before unicast and multicast filtering 1h
  • CVE-2026-99210 accel/rocket: clear rdev on device init failure 1h
  • CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 1h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-99213 is "vsock: treat TCP_CLOSING as once-established", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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