Kernel Memory Corruption in ZFS by FreeBSD
CVE-2026-49430

Currently unrated

Key Information:

Vendor: FreeBSD
Status: FreeBSD
Vendor: CVE Published:; 19 August 2026

What is CVE-2026-49430?

A vulnerability in ZFS, specifically within the ZFS_IOC_RECV_NEW ioctl during the heal receive path, allows local users with receive delegated ZFS permissions to induce kernel memory corruption. This occurs when a crafted receive stream is sent in heal mode, leading to a truncation of a 64-bit payload size to a 32-bit integer used for allocation. The operation subsequently attempts to use the original 64-bit size for a byteswap operation, creating potential stability and security risks within the system.

Affected Version(s)

FreeBSD 15.1-RELEASE

FreeBSD 15.0-RELEASE

FreeBSD 14.4-RELEASE

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:40....

vendor-advisory

Download the Critical Vulnerability Management Cheat Sheet

Timeline

Vulnerability published
Aug 19, 2026
Vulnerability Reserved
May 29, 2026

Credit

Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai

Emmanuel Genier at Quarkslab

CVE-2026-49430 Data

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