CVE-2026-43194Network attack vector

TCP connection stall via misread GSO errors

Published May 6, 2026 · Updated May 6, 2026

Denial of service in the Linux Kernel network transmit path allows remote attackers to stall TCP connections after packet loss. In tcp_write_xmit, the kernel treats an error for the final segment of a GSO frame as proof that the entire frame was unsent, leaving snd_nxt behind data already received. The failure requires GSO traffic over a device without a Qdisc; subsequent ACKs are rejected as unsent data, and the affected connection remains stuck.

CVSS severity7.5
High
EPSS probability0.53%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux Kernel network transmit path allows remote attackers to stall TCP connections after packet loss. In tcp_write_xmit, the kernel treats an error for the final segment of a GSO frame as proof that the entire frame was unsent, leaving snd_nxt behind data already received. The failure requires GSO traffic over a device without a Qdisc; subsequent ACKs are rejected as unsent data, and the affected connection remains stuck.

The record

CVE
CVE-2026-43194
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <0c9de092ef8c50a7ee9612811566f0aa81d8d7b6
  2. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <4cb163e9efcac4cd35c3043e097f25081a5c015c
  3. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <56bd32c0edca34041a5c215887fcf562fae2e2db
  4. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <7aa767d0d3d04e50ae94e770db7db8197f666970
  5. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <9ac6aebef4b4bfc5ed408b0b65645981574bc780
  6. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <ae3f627b45fbc3c776a4e484696f3cad7cbb4eca
  7. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <c86901d22c89a6bf4e2f013e948aaabc60869893
  8. Affected versionversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <ea5d7787635e26ec1194ec7eec0e8e5ae3bd10a5
  9. Affected versionversion=3.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <0c9de092ef8c50a7ee9612811566f0aa81d8d7b6; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <4cb163e9efcac4cd35c3043e097f25081a5c015c; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <56bd32c0edca34041a5c215887fcf562fae2e2db; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <7aa767d0d3d04e50ae94e770db7db8197f666970; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <9ac6aebef4b4bfc5ed408b0b65645981574bc780; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <ae3f627b45fbc3c776a4e484696f3cad7cbb4eca; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <c86901d22c89a6bf4e2f013e948aaabc60869893; version=1f59533f9ca5634e7b8914252e48aee9d9cbe501 <ea5d7787635e26ec1194ec7eec0e8e5ae3bd10a5; version=3.18

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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