CVE-2026-43496

Kernel panic via mismatched child-qdisc dequeue

Published May 21, 2026 · Updated May 21, 2026

NULL pointer dereference in the Linux Kernel sch_red scheduler allows local users to trigger a kernel panic through an affected qdisc hierarchy. In red_dequeue, sch_red peeks a packet from a child qdisc but then directly dequeues from that child instead of consuming the previously peeked gso_skb entry. A RED qdisc must have a child such as QFQ whose peek callback uses qdisc_peek_dequeued; exercising that hierarchy can dereference NULL and crash the host.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux Kernel sch_red scheduler allows local users to trigger a kernel panic through an affected qdisc hierarchy. In red_dequeue, sch_red peeks a packet from a child qdisc but then directly dequeues from that child instead of consuming the previously peeked gso_skb entry. A RED qdisc must have a child such as QFQ whose peek callback uses qdisc_peek_dequeued; exercising that hierarchy can dereference NULL and crash the host.

The record

CVE
CVE-2026-43496
Published
May 21, 2026
Updated
May 21, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2026CVE publishedPublication date reported by the CVE source.
  2. May 21, 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=2.6.29
  2. Affected versionversion=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <36aa34f42cb6842cf371f3a2d3e855d24fd57a50
  3. Affected versionversion=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <458d5615272d3de535748342eb68ca492343048c
  4. Affected versionversion=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <587dcf970a525f543d8b5855d9f37a4ca97b76ef
  5. Affected versionversion=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <8d09618840b99ef00154d3e731ce9b11e096196d
  6. Affected versionversion=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <ce051eede433f876d322ac3550a36a3c6fc4c231

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.29; version=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <36aa34f42cb6842cf371f3a2d3e855d24fd57a50; version=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <458d5615272d3de535748342eb68ca492343048c; version=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <587dcf970a525f543d8b5855d9f37a4ca97b76ef; version=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <8d09618840b99ef00154d3e731ce9b11e096196d; version=77be155cba4e163e8bba9fd27222a8b6189ec4f7 <ce051eede433f876d322ac3550a36a3c6fc4c231

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.4Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:H/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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