CVE-2026-98276Hinoki check available

Local kernel use-after-free via timestamp flag race

Published Oct 6, 2026 · Updated Oct 6, 2026

A socket flag race in Linux allows local users to trigger a UDP socket use-after-free through concurrent timestamp ioctl and bind calls. In sock_gettstamp(), an unlocked, non-atomic update to sk_flags can erase SOCK_RCU_FREE, causing sk_destruct() to free a socket still visible to lockless UDP receive lookups. The trigger requires local socket access and a concurrent receive path; the published report demonstrates an invalid kernel read, not privilege escalation.

CVSS severityUnavailable
Unscored
EPSS probability0.14%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

A socket flag race in Linux allows local users to trigger a UDP socket use-after-free through concurrent timestamp ioctl and bind calls. In sock_gettstamp(), an unlocked, non-atomic update to sk_flags can erase SOCK_RCU_FREE, causing sk_destruct() to free a socket still visible to lockless UDP receive lookups. The trigger requires local socket access and a concurrent receive path; the published report demonstrates an invalid kernel read, not privilege escalation.

The record

CVE
CVE-2026-98276
Published
Oct 6, 2026
Updated
Oct 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 6, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <18899e2e4023369a8f7739c2255a59a9748d8d17
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1f73253add8365d0dad0a4f421acaa8c21d20cef
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3b12d3967e96f1b7b977d9fc352ae29a1b299a82
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <88c804847dd87dc613b771b392ccecdb94725032
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <899650bbf985b7bfd2a7b808357df9b16e6d6959
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9ed55f3dbef4f4adfe65eb03b0c35c53229a8490
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d9f96bc2d822501f84d1caa6275a2c6b316ca2c4
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <18899e2e4023369a8f7739c2255a59a9748d8d17; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1f73253add8365d0dad0a4f421acaa8c21d20cef; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3b12d3967e96f1b7b977d9fc352ae29a1b299a82; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <88c804847dd87dc613b771b392ccecdb94725032; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <899650bbf985b7bfd2a7b808357df9b16e6d6959; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9ed55f3dbef4f4adfe65eb03b0c35c53229a8490; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d9f96bc2d822501f84d1caa6275a2c6b316ca2c4; version=2.6.12

Published CVSS scores

No CVSS assessment is available in this record.

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.

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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

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