CVE-2026-64000Network attack vector

Out-of-bounds access via truncated supervision frame

Published Jul 19, 2026 · Updated Jul 19, 2026

Out-of-bounds access in the Linux Kernel HSR subsystem allows remote attackers to disrupt kernel operation via a truncated supervision frame. In is_supervision_frame in net/hsr/hsr_forward.c, pskb_may_pull checks only through the preceding payload before code reads the following hsr_sup_tlv type and length. Reachability requires an HSR- or PRP-configured Linux node and delivery of a crafted layer-2 supervision frame; the published record establishes out-of-bounds kernel-memory access but does not specify a resulting crash or disclosure.

CVSS severity9.8
Critical
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in the Linux Kernel HSR subsystem allows remote attackers to disrupt kernel operation via a truncated supervision frame. In is_supervision_frame in net/hsr/hsr_forward.c, pskb_may_pull checks only through the preceding payload before code reads the following hsr_sup_tlv type and length. Reachability requires an HSR- or PRP-configured Linux node and delivery of a crafted layer-2 supervision frame; the published record establishes out-of-bounds kernel-memory access but does not specify a resulting crash or disclosure.

The record

CVE
CVE-2026-64000
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.16
  2. Affected versionversion=eafaa88b3eb7f28aecb222281655473431d3ef2e <09a37dca090c55ffb1a33f52d8667f1c2367ef48
  3. Affected versionversion=eafaa88b3eb7f28aecb222281655473431d3ef2e <71c986c0ba45b7dc574fae27c83e7b6671556f37
  4. Affected versionversion=eafaa88b3eb7f28aecb222281655473431d3ef2e <78607a6854a22a2502f68092202e75a39af4865d
  5. Affected versionversion=eafaa88b3eb7f28aecb222281655473431d3ef2e <a4b64f3e9c7b8259f7dd251a0313420ba7c01852
  6. Affected versionversion=eafaa88b3eb7f28aecb222281655473431d3ef2e <f229426072fc865654a60978bb7fda790a051ff3
  7. Affected versionversion=eafaa88b3eb7f28aecb222281655473431d3ef2e <fbd0662f9c9a66e8cc3df3099cca8ed6d3837cc7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.16; version=eafaa88b3eb7f28aecb222281655473431d3ef2e <09a37dca090c55ffb1a33f52d8667f1c2367ef48; version=eafaa88b3eb7f28aecb222281655473431d3ef2e <71c986c0ba45b7dc574fae27c83e7b6671556f37; version=eafaa88b3eb7f28aecb222281655473431d3ef2e <78607a6854a22a2502f68092202e75a39af4865d; version=eafaa88b3eb7f28aecb222281655473431d3ef2e <a4b64f3e9c7b8259f7dd251a0313420ba7c01852; version=eafaa88b3eb7f28aecb222281655473431d3ef2e <f229426072fc865654a60978bb7fda790a051ff3; version=eafaa88b3eb7f28aecb222281655473431d3ef2e <fbd0662f9c9a66e8cc3df3099cca8ed6d3837cc7

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/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)
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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