CVE-2026-74748Hinoki check available

Kernel panic via stale ipset refcount decrement

Published Aug 26, 2026 · Updated Aug 27, 2026

A refcount race in the Linux kernel netfilter ipset component allows local users to crash the system via concurrent list:set cleanup and swaps. The __ip_set_put_byindex() path resolves an index under RCU, then decrements a stale set pointer after ip_set_swap() can exchange the indexed set and its reference count. CAP_NET_ADMIN for IPSET_CMD_SWAP is required, but a user namespace can grant it without init-namespace root; the demonstrated outcome is a kernel panic.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

A refcount race in the Linux kernel netfilter ipset component allows local users to crash the system via concurrent list:set cleanup and swaps. The __ip_set_put_byindex() path resolves an index under RCU, then decrements a stale set pointer after ip_set_swap() can exchange the indexed set and its reference count. CAP_NET_ADMIN for IPSET_CMD_SWAP is required, but a user namespace can grant it without init-namespace root; the demonstrated outcome is a kernel panic.

The record

CVE
CVE-2026-74748
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-367, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 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=3.8
  2. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <0c88868271653537ed443272dd8e7d13634d214b
  3. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <20cb13a523f0a05cb2d0a7d72abae687683712e0
  4. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <24ffcb1e1688c55fd2a505f064295cd28eac546d
  5. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <97a01de0c6321b7210d30d0a4d60f10f561097c7
  6. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <b0aab9dd1a348b99d75ff52765719d0cc2050630
  7. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <b891e7a6bb06e0f6560e5932665ac660acd12225
  8. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <c21afc7c216a4d257a4f3f300e0791890bc846b9
  9. Affected versionversion=9076aea76538556224e7d73ab718f8841330818a <cb20da33839f28f590c99f16bafaa6151451c0e8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.8; version=9076aea76538556224e7d73ab718f8841330818a <0c88868271653537ed443272dd8e7d13634d214b; version=9076aea76538556224e7d73ab718f8841330818a <20cb13a523f0a05cb2d0a7d72abae687683712e0; version=9076aea76538556224e7d73ab718f8841330818a <24ffcb1e1688c55fd2a505f064295cd28eac546d; version=9076aea76538556224e7d73ab718f8841330818a <97a01de0c6321b7210d30d0a4d60f10f561097c7; version=9076aea76538556224e7d73ab718f8841330818a <b0aab9dd1a348b99d75ff52765719d0cc2050630; version=9076aea76538556224e7d73ab718f8841330818a <b891e7a6bb06e0f6560e5932665ac660acd12225; version=9076aea76538556224e7d73ab718f8841330818a <c21afc7c216a4d257a4f3f300e0791890bc846b9; version=9076aea76538556224e7d73ab718f8841330818a <cb20da33839f28f590c99f16bafaa6151451c0e8

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8LinuxCVSS:3.1/AV:L/AC:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
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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