CVE-2024-49936

Guest-to-host compromise via unsafe RCU hash traversal

Published Oct 21, 2024 · Updated Aug 5, 2026

Use-after-free in the Linux Xen netback driver allows guest OS users to compromise the host kernel via control-ring requests. xenvif_flush_hash() traverses the hash cache with list_for_each_entry_rcu while kfree_rcu can free the current entry, so head->next accesses freed memory. Reachability requires a Xen guest with a virtual network interface; repeated SET_HASH_KEY requests can cause host data disclosure, memory writes, or a crash.

CVSS severity8.8
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux Xen netback driver allows guest OS users to compromise the host kernel via control-ring requests. xenvif_flush_hash() traverses the hash cache with list_for_each_entry_rcu while kfree_rcu can free the current entry, so head->next accesses freed memory. Reachability requires a Xen guest with a virtual network interface; repeated SET_HASH_KEY requests can cause host data disclosure, memory writes, or a crash.

The record

CVE
CVE-2024-49936
Published
Oct 21, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 21, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <0fa5e94a1811d68fbffa0725efe6d4ca62c03d12
  2. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <143edf098b80669d05245b2f2367dd156a83a2c5
  3. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <3c4423b0c4b98213b3438e15061e1d08220e6982
  4. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <54d8639af5568fc41c0e274fc3ec9cf86c59fcbb
  5. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <a0465723b8581cad27164c9073fd780904cd22d4
  6. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <a7f0073fcd12ed7de185ef2c0af9d0fa1ddef22c
  7. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <d408889d4b54f5501e4becc4dbbb9065143fbf4e
  8. Affected versionversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <efcff6ce7467f01f0753609f420333f3f2ceceda
  9. Affected versionversion=4.7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <0fa5e94a1811d68fbffa0725efe6d4ca62c03d12; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <143edf098b80669d05245b2f2367dd156a83a2c5; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <3c4423b0c4b98213b3438e15061e1d08220e6982; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <54d8639af5568fc41c0e274fc3ec9cf86c59fcbb; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <a0465723b8581cad27164c9073fd780904cd22d4; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <a7f0073fcd12ed7de185ef2c0af9d0fa1ddef22c; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <d408889d4b54f5501e4becc4dbbb9065143fbf4e; version=40d8abdee806d496a60ee607a6d01b1cd7fabaf0 <efcff6ce7467f01f0753609f420333f3f2ceceda; version=4.7

Published CVSS scores

8.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.8NIST NVDCVSS: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 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-416Use After Free
T1068Exploitation for Privilege Escalation

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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