CVE-2026-72347

Packet-mark disruption via unchecked shift parameters

Published Aug 15, 2026 · Updated Aug 15, 2026

Incorrect bitwise shifting in the Linux kernel allows local users to disrupt packet marking with a malformed revision-2 CONNMARK rule. connmark_tg_check() accepts shift_bits values of 32 or more and invalid shift_dir values, letting connmark_tg_shift() perform an undefined 32-bit shift or silently choose the left-shift path. Reachability requires installing a malformed revision-2 CONNMARK rule before packet evaluation triggers the faulty mark operation.

CVSS severity7.3
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect bitwise shifting in the Linux kernel allows local users to disrupt packet marking with a malformed revision-2 CONNMARK rule. connmark_tg_check() accepts shift_bits values of 32 or more and invalid shift_dir values, letting connmark_tg_shift() perform an undefined 32-bit shift or silently choose the left-shift path. Reachability requires installing a malformed revision-2 CONNMARK rule before packet evaluation triggers the faulty mark operation.

The record

CVE
CVE-2026-72347
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-1335
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=4.17
  2. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <1b47026fb4b35bac850ad6e8a4ad7fc018e09ebc
  3. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <230173cc6105bdfb2696d37e6e56687b003fbe63
  4. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <4eef84b09a3836919360c4232b0f16651a155eec
  5. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <8ace320ac4416f5e5fbcd065309fb2dfcce787b0
  6. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <9657bb11a6376ab0a79f05d433713d6944111e9d
  7. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <c3fa852d117b3fda72265e4230e3967db4a74fcf
  8. Affected versionversion=472a73e00757b971d613d796374d2727b2e4954d <d8ce63d928b457fba7ed1e302492dfd32293671c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.17; version=472a73e00757b971d613d796374d2727b2e4954d <1b47026fb4b35bac850ad6e8a4ad7fc018e09ebc; version=472a73e00757b971d613d796374d2727b2e4954d <230173cc6105bdfb2696d37e6e56687b003fbe63; version=472a73e00757b971d613d796374d2727b2e4954d <4eef84b09a3836919360c4232b0f16651a155eec; version=472a73e00757b971d613d796374d2727b2e4954d <8ace320ac4416f5e5fbcd065309fb2dfcce787b0; version=472a73e00757b971d613d796374d2727b2e4954d <9657bb11a6376ab0a79f05d433713d6944111e9d; version=472a73e00757b971d613d796374d2727b2e4954d <c3fa852d117b3fda72265e4230e3967db4a74fcf; version=472a73e00757b971d613d796374d2727b2e4954d <d8ce63d928b457fba7ed1e302492dfd32293671c

Published CVSS scores

7.3NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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-1335Incorrect Bitwise Shift of Integer

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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