CVE-2026-74270

Local TLS bypass via unchecked DONE command

Published Aug 15, 2026 · Updated Aug 15, 2026

Authentication bypass in Linux 6.4 and later affected branches allows local users to forge or abort kernel TLS handshakes. handshake_nl_done_doit accepts an unprivileged generic-Netlink DONE message after checking only that its socket descriptor has a pending request, without authenticating the sender. A local low-privileged process must guess or observe that descriptor; forged success bypasses peer verification, while failure interrupts session establishment.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Linux 6.4 and later affected branches allows local users to forge or abort kernel TLS handshakes. handshake_nl_done_doit accepts an unprivileged generic-Netlink DONE message after checking only that its socket descriptor has a pending request, without authenticating the sender. A local low-privileged process must guess or observe that descriptor; forged success bypasses peer verification, while failure interrupts session establishment.

The record

CVE
CVE-2026-74270
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-290
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=3b3009ea8abb713b022d94fba95ec270cf6e7eae <25fb53e43ec006ac69b9e825a7e8a11d63a6083e
  2. Affected versionversion=3b3009ea8abb713b022d94fba95ec270cf6e7eae <4dafc411948469277b276724c3b2b4408c02c04c
  3. Affected versionversion=3b3009ea8abb713b022d94fba95ec270cf6e7eae <67cec2f1eb9e58719d622e92e2278ceda72dbd85
  4. Affected versionversion=3b3009ea8abb713b022d94fba95ec270cf6e7eae <81246a65303d9635266b1334490142caaf86a11f
  5. Affected versionversion=3b3009ea8abb713b022d94fba95ec270cf6e7eae <b6557f912509abe8e70223373dd7a44d1d4a0d6c
  6. Affected versionversion=6.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3b3009ea8abb713b022d94fba95ec270cf6e7eae <25fb53e43ec006ac69b9e825a7e8a11d63a6083e; version=3b3009ea8abb713b022d94fba95ec270cf6e7eae <4dafc411948469277b276724c3b2b4408c02c04c; version=3b3009ea8abb713b022d94fba95ec270cf6e7eae <67cec2f1eb9e58719d622e92e2278ceda72dbd85; version=3b3009ea8abb713b022d94fba95ec270cf6e7eae <81246a65303d9635266b1334490142caaf86a11f; version=3b3009ea8abb713b022d94fba95ec270cf6e7eae <b6557f912509abe8e70223373dd7a44d1d4a0d6c; version=6.4

Published CVSS scores

7.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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