Vulnerability · CVE-2026-99213

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

Published Oct 28, 2026 · catalog updated Nov 1, 2026 · Linux Linux

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-99213. EPSS is 0.13%. Act only if a listed version of Linux Linux is installed.

Gaps on this record

No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

CVE-2026-99284 · Unknown
CVE-2026-99283 · Low
CVE-2026-99260 · Medium
CVE-2026-99259 · Medium
CVE-2026-99258 · High

Severity: High7.8
Known exploitation: Not in CISA/VulnCheck KEV
EPSS: 0.13%
Remediation: Advisory link
Affected products: Debian:12 linux · Debian:13 linux · Debian:14 linux · Ubuntu:16.04:LTS linux-hwe-edge · Ubuntu:Pro:14.04:LTS linux · Ubuntu:Pro:14.04:LTS linux-aws

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

Debian:12 linux6.1.106-1, 6.1.106-2, 6.1.106-3
Debian:13 linux6.12.100-1, 6.12.101-1, 6.12.105-1
Debian:14 linux6.12.100-1, 6.12.101-1, 6.12.105-1
Ubuntu:16.04:LTS linux-hwe-edge4.8.0-28.30~16.04.1, 4.8.0-30.32~16.04.1, 4.8.0-32.34~16.04.1
Ubuntu:Pro:14.04:LTS linux3.11.0-12.19, 3.12.0-1.3, 3.12.0-2.5
Ubuntu:Pro:14.04:LTS linux-aws4.4.0-1002.2, 4.4.0-1003.3, 4.4.0-1005.5
Ubuntu:Pro:14.04:LTS linux-azure4.15.0-1023.24~14.04.1, 4.15.0-1030.31~14.04.1, 4.15.0-1031.32~14.04.1
Ubuntu:Pro:14.04:LTS linux-lts-xenial4.4.0-13.29~14.04.1, 4.4.0-14.30~14.04.2, 4.4.0-15.31~14.04.1
Ubuntu:Pro:16.04:LTS linux4.2.0-16.19, 4.2.0-17.21, 4.2.0-19.23
Ubuntu:Pro:16.04:LTS linux-aws4.4.0-1001.10, 4.4.0-1003.12, 4.4.0-1004.13
Ubuntu:Pro:16.04:LTS linux-aws-hwe4.15.0-1030.31~16.04.1, 4.15.0-1031.33~16.04.1, 4.15.0-1032.34~16.04.1
Ubuntu:Pro:16.04:LTS linux-azure4.11.0-1009.9, 4.11.0-1011.11, 4.11.0-1013.13
Ubuntu:Pro:16.04:LTS linux-gcp4.10.0-1004.4, 4.10.0-1006.6, 4.10.0-1007.7
Ubuntu:Pro:16.04:LTS linux-hwe4.8.0-36.36~16.04.1, 4.8.0-39.42~16.04.1, 4.8.0-41.44~16.04.1
Ubuntu:Pro:16.04:LTS linux-kvm4.4.0-1004.9, 4.4.0-1007.12, 4.4.0-1008.13
linux kernelversion unspecified
vendor Linux Linuxversion unspecified

How to fix CVE-2026-99213

No stored fix
No vendor fix text is stored. Use the linked advisory before you change production.
Version check
Seen in 6.1.106-1 · 17 other packages on the advisory
Advisory
Open the bsi record and follow its fix.
Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-99213. EPSS is 0.13%. Act only if a listed version of Linux Linux is installed.

Which versions are affected?

Compare what you have installed with 6.1.106-1, 6.1.106-2, 6.1.106-3, 6.12.100-1, 6.12.101-1, 6.12.105-1, 4.8.0-28.30~16.04.1, 4.8.0-30.32~16.04.1, 4.8.0-32.34~16.04.1, 3.11.0-12.19, 3.12.0-1.3, 3.12.0-2.5, 4.4.0-1002.2, 4.4.0-1003.3, 4.4.0-1005.5, 4.15.0-1023.24~14.04.1, 4.15.0-1030.31~14.04.1, 4.15.0-1031.32~14.04.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.13%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Debian security Ubuntu security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

Oct 28, 2026 · Tenable CVE Database
Detected
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 o
Oct 28, 2026 · CVE.org
Updated
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 o
Oct 30, 2026 · OpenSSF OSV / OSV Scanner
Updated
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 o
Nov 1, 2026 · Trivy Vulnerability DB
Updated
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 o

Sources

BSI CERT-BundGovernment advisoryCVE-2026-99213
Linux Kernel: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff
wid.cert-bund.de
CVE.orgVulnerability recordCVE-2026-99213
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
cve.org
FIRST EPSSExploitation probabilityCVE-2026-99213
30-day exploitation probability 0.13%
first.org
Linux Kernel CVEVendor advisoryCVE-2026-99213
From: Greg Kroah-Hartman Description =========== 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 brea
git.kernel.org
OpenSSF OSV / OSV ScannerPackage advisoryUBUNTU-CVE-2026-99213
osv.dev
Tenable CVE DatabaseVulnerability recordCVE-2026-99213
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 o
tenable.com
Trivy Vulnerability DBPackage advisoryDEBIAN-CVE-2026-99213
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
osv.dev

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

FIRST EPSSNov 7, 2026
Trivy Vulnerability DBNov 1, 2026
OpenSSF OSV / OSV ScannerOct 31, 2026
BSI CERT-BundOct 30, 2026
CVE.orgOct 28, 2026
Linux Kernel CVEOct 28, 2026
Tenable CVE DatabaseOct 28, 2026

Priority score

24/100

Evidence confidence: High

A vendor or government advisory agrees with at least one other source.

Confirmed exploitation0/30
EPSS probability1/20
CVSS severity12/15
Public exploit0/10
Internet exposure6/10
Product prevalence5/5
Detection0/5
Threat research0/5

Decision signals

Four separate signals — do not infer one from another.

High

CVSS severity
7.8 v3.1
Technical impact. Separate from exploitation likelihood.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS probability
0.13% · p2.17%
Estimated probability of exploitation within 30 days (FIRST).
Known exploitation
No verified KEV listing
Evidence from CISA KEV or VulnCheck KEV only — not from EPSS alone.
Patch availability
Advisory link
A patch or advisory reference is linked. Open the original publisher for availability by product version.

Stacks

Debian Debian 12 Debian 13 Debian 14 Linux Ubuntu Ubuntu 14.04 Ubuntu 16.04

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