CVE-2026-90248Hinoki check available

Classifier removal via insert-race ownership confusion

Published Sep 17, 2026 · Updated Sep 17, 2026

Race condition in Linux Kernel 5.1 allows local users to remove active packet classifiers via concurrent filter creation requests. In net/sched/cls_api.c, tc_new_tfilter() retains its creation flag after losing an insertion race, causing error cleanup to unlink the winning request's live classifier. Triggering requires CAP_NET_ADMIN in the relevant network namespace and competing requests at the same chain and priority; the documented consequence is silent classifier removal, not a kernel crash.

CVSS severity3.6
Low
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Race condition in Linux Kernel 5.1 allows local users to remove active packet classifiers via concurrent filter creation requests. In net/sched/cls_api.c, tc_new_tfilter() retains its creation flag after losing an insertion race, causing error cleanup to unlink the winning request's live classifier. Triggering requires CAP_NET_ADMIN in the relevant network namespace and competing requests at the same chain and priority; the documented consequence is silent classifier removal, not a kernel crash.

The record

CVE
CVE-2026-90248
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
Linux Foundation
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=5.1
  2. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <219c87aeefdcc8c1caf28cc99e9b361ce7393d3a
  3. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <a68e664ddf16ecae6d769d6a2eb356f8abab75c9
  4. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <bbe2fd6d77df630356185406a97317f6aa6a92cf
  5. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <bee2208276c8e0e40a249ffdcf6e5434a79a847c
  6. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <d4e359b3608a0e184bbe8d61a5c3b50d0831c44a
  7. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <dc8b33b819cb02a75936940c120aa669ad89942d
  8. Affected versionversion=8b64678e0af8f4d62a40149baedebe78503a5255 <df02b6dc136af45e92ee4c86f4aa6c9a60790b1e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Linux Foundation · Linux Kernelversion=5.1; version=8b64678e0af8f4d62a40149baedebe78503a5255 <219c87aeefdcc8c1caf28cc99e9b361ce7393d3a; version=8b64678e0af8f4d62a40149baedebe78503a5255 <a68e664ddf16ecae6d769d6a2eb356f8abab75c9; version=8b64678e0af8f4d62a40149baedebe78503a5255 <bbe2fd6d77df630356185406a97317f6aa6a92cf; version=8b64678e0af8f4d62a40149baedebe78503a5255 <bee2208276c8e0e40a249ffdcf6e5434a79a847c; version=8b64678e0af8f4d62a40149baedebe78503a5255 <d4e359b3608a0e184bbe8d61a5c3b50d0831c44a; version=8b64678e0af8f4d62a40149baedebe78503a5255 <dc8b33b819cb02a75936940c120aa669ad89942d; version=8b64678e0af8f4d62a40149baedebe78503a5255 <df02b6dc136af45e92ee4c86f4aa6c9a60790b1e

Published CVSS scores

3.6Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L
3.6SUSECVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started