CVE-2026-43057Network attack vector

Service interruption via incorrect tunneled GSO fallback

Published May 1, 2026 · Updated May 1, 2026

Incorrect GSO fallback in the Linux kernel allows remote attackers to interrupt service through crafted tunneled IPv6 traffic. The gso_features_check path tests the outer network-header length for encapsulated packets instead of the inner header and leaves TSO enabled when software GSO is required. Exposure requires tunneled IPv6 packets with extension headers, or tunnels without an inner IP protocol, on a device advertising NETIF_F_IPV6_CSUM.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect GSO fallback in the Linux kernel allows remote attackers to interrupt service through crafted tunneled IPv6 traffic. The gso_features_check path tests the outer network-header length for encapsulated packets instead of the inner header and leaves TSO enabled when software GSO is required. Exposure requires tunneled IPv6 packets with extension headers, or tunnels without an inner IP protocol, on a device advertising NETIF_F_IPV6_CSUM.

The record

CVE
CVE-2026-43057
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 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=041e2f945f82fdbd6fff577b79c33469430297aa <33670f780e0120c3dacda188c512bbffe0b6044c
  2. Affected versionversion=2156d9e9f2e483c8c3906c0ea57ea312c1424235 <ed71cf465c75f5688b07a35d373cd1d6b589c8ea
  3. Affected versionversion=6.17
  4. Affected versionversion=794ddbb7b63b6828c75967b9bcd43b086716e7a1
  5. Affected versionversion=864e3396976ef41de6cc7bc366276bf4e084fff2 <732fdeb2987c94b439d51f5cb9addddc2fc48c42
  6. Affected versionversion=864e3396976ef41de6cc7bc366276bf4e084fff2 <a98b78116a27e2a57b696b569b2cb431c95cf9b6
  7. Affected versionversion=864e3396976ef41de6cc7bc366276bf4e084fff2 <c4336a07eb6b2526dc2b62928b5104b41a7f81f5
  8. Affected versionversion=a0478d7e888028f85fa7785ea838ce0ca09398e2 <2094a7cf91b71367b649f991aacc7b579f793d0b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=041e2f945f82fdbd6fff577b79c33469430297aa <33670f780e0120c3dacda188c512bbffe0b6044c; version=2156d9e9f2e483c8c3906c0ea57ea312c1424235 <ed71cf465c75f5688b07a35d373cd1d6b589c8ea; version=6.17; version=794ddbb7b63b6828c75967b9bcd43b086716e7a1; version=864e3396976ef41de6cc7bc366276bf4e084fff2 <732fdeb2987c94b439d51f5cb9addddc2fc48c42; version=864e3396976ef41de6cc7bc366276bf4e084fff2 <a98b78116a27e2a57b696b569b2cb431c95cf9b6; version=864e3396976ef41de6cc7bc366276bf4e084fff2 <c4336a07eb6b2526dc2b62928b5104b41a7f81f5; version=a0478d7e888028f85fa7785ea838ce0ca09398e2 <2094a7cf91b71367b649f991aacc7b579f793d0b

Published CVSS scores

7.5CanonicalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5OracleCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5kernel.orgCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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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