CVE-2026-49429

Privilege escalation via truncated ioctl size

Published Aug 19, 2026 · Updated Aug 20, 2026

Heap overflow in ZFS in FreeBSD allows local users with delegated permissions to escalate privileges via a crafted ioctl request. The ZFS_IOC_USERSPACE_MANY handler truncates a 64-bit userspace output size to 32 bits for kernel allocation, then uses the original 64-bit size as the limit while writing records into that buffer. Reachability requires local access plus the delegated ZFS "userused" permission; affected releases are 14.3-RELEASE before p16, 14.4-RELEASE before p7, 15.0-RELEASE before p11, and 15.1-RELEASE before p1.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in ZFS in FreeBSD allows local users with delegated permissions to escalate privileges via a crafted ioctl request. The ZFS_IOC_USERSPACE_MANY handler truncates a 64-bit userspace output size to 32 bits for kernel allocation, then uses the original 64-bit size as the limit while writing records into that buffer. Reachability requires local access plus the delegated ZFS "userused" permission; affected releases are 14.3-RELEASE before p16, 14.4-RELEASE before p7, 15.0-RELEASE before p11, and 15.1-RELEASE before p1.

The record

CVE
CVE-2026-49429
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-122, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 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=14.3-RELEASE <p16
  2. Affected versionversion=14.4-RELEASE <p7
  3. Affected versionversion=15.0-RELEASE <p11
  4. Affected versionversion=15.1-RELEASE <p1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=14.3-RELEASE <p16; version=14.4-RELEASE <p7; version=15.0-RELEASE <p11; version=15.1-RELEASE <p1

Published CVSS scores

7.8CISA ADPCVSS: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-122Heap-based Buffer Overflow
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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