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CVE-2026-58086— ktrace(2) privilege incorrectly validated in jails

Quick assessment

Affected
FreeBSD FreeBSD
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

由于一个无关代码变更的意外副作用，被关在 jail 环境中的 root 用户始终无法获得 PRIV_KTRACE 权限。因此，由 jail 内的 root 用户配置的跟踪（tracing）未被标记为特权操作。 在一个允许非特权用户调试目标进程的 jail 环境中，该非特权用户可以修改 jail 内 root 用户的 ktrace(2) 标志，或者直接禁用跟踪功能。因此，jail 内的 root 用户无法可靠地跟踪非特权进程。

AI Predicted 5.3 Difficulty: Moderate EPSS 0.18% · P8

Possible ATT&CK Techniques 1 AI

T1055 · Process Injection

Affected Version Matrix 2

VendorProduct Version RangeStatus
FreeBSD FreeBSD 15.1-RELEASE< p2 affected
15.0-RELEASE< p12 affected
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I. Basic Information for CVE-2026-58086

Vulnerability Information
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Vulnerability Title
ktrace(2) privilege incorrectly validated in jails
Source: CVE Program / CVE List V5
Vulnerability Description
As an inadvertent side effect of an unrelated code change, PRIV_KTRACE was always denied to a jailed root user. Tracing configured by a jailed root user was therefore not flagged as privileged. An unprivileged user in a jail that has permission to debug the target process can modify the jailed root user's ktrace(2) flags, or disable tracing outright. A jailed root user therefore cannot reliably trace unprivileged processes.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
对于放弃特权的检查不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
FreeBSD FreeBSD 15.1-RELEASE ~ p2 -

II. Public POCs for CVE-2026-58086

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III. Intelligence Information for CVE-2026-58086

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Vendor Advisories for CVE-2026-58086 (1)

Same Patch Batch · FreeBSD · 2026-08-19 · 23 CVEs total

CVE-2026-49426 Incorrect audit records for ptrace(2) syscall requests
CVE-2026-58087 Heap out-of-bounds access in semctl(2)
CVE-2026-58088 Race condition in ELF core dump segment counting
CVE-2026-58083 Use-after-free in kqueue copy-on-fork
CVE-2026-58084 Kernel stack disclosure via timer_settime(2)
CVE-2026-58085 Missing MAC validation in wg(4) packet decryption
CVE-2026-49425 Kernel stack disclosure in 32-bit compatibility support
CVE-2026-49424 Kernel stack disclosure in Linux compatibility layer
CVE-2026-58081 Heap based buffer overflow in iconv(3)
CVE-2026-58082 Stack based buffer overflow in iconv(3)
CVE-2026-49423 Remote DOS via uninitialized memory access in KTLS receive
CVE-2026-49418 Use-after-free in device pager page list
CVE-2026-49427 posixshm: largepage shared memory objects not explicitly wired
CVE-2026-49428 posixshm: system calls can incorrectly free memory of largepage objects
CVE-2026-49420 Buffer overflow in libalias RTSP handler
CVE-2026-49422 Use-after-free in TCP RACK stack option handler
CVE-2026-49421 unlinkat(2) ignores AT_RESOLVE_BENEATH flag
CVE-2026-49430 Kernel heap overflow in ZFS_IOC_RECV_NEW ioctl
CVE-2026-49429 Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl
CVE-2026-49431 Incorrect user validation in ZFS_IOC_SET_PROP ioctl

Showing top 20 of 23 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: FreeBSD
Same vendor: FreeBSD
Same weakness: CWE-273

V. Comments for CVE-2026-58086

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