CVE-2026-49430

Kernel memory corruption via size truncation

Published Aug 19, 2026 · Updated Aug 19, 2026

Memory corruption in ZFS in FreeBSD allows local users to corrupt kernel memory via a crafted heal-mode receive stream. The ZFS_IOC_RECV_NEW ioctl truncates a 64-bit payload size to 32 bits when allocating memory in the heal receive path, then uses the original 64-bit size as the length for a byteswap operation. Reachability requires local access with delegated ZFS receive permission; public records describe kernel memory corruption but do not document demonstrated privilege escalation or code execution for this CVE.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in ZFS in FreeBSD allows local users to corrupt kernel memory via a crafted heal-mode receive stream. The ZFS_IOC_RECV_NEW ioctl truncates a 64-bit payload size to 32 bits when allocating memory in the heal receive path, then uses the original 64-bit size as the length for a byteswap operation. Reachability requires local access with delegated ZFS receive permission; public records describe kernel memory corruption but do not document demonstrated privilege escalation or code execution for this CVE.

The record

CVE
CVE-2026-49430
Published
Aug 19, 2026
Updated
Aug 19, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-122
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 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

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.

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

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

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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