CVE-2026-49429
Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in p1, p11, p7, p16
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records. A local user with the "userused" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges.
Timeline
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- CVE published
- Record last updated
Affected versions
- FreeBSD FreeBSD
From 15.1-RELEASE · fixed in p1; From 15.0-RELEASE · fixed in p11; From 14.4-RELEASE · fixed in p7; From 14.3-RELEASE · fixed in p16