CVE-2026-46333

Published May 15, 2026

Last updated 20 hours ago

Linux Kernel

Ptrace

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-46333, publicly known as "ssh-keysign-pwn," is a local information disclosure vulnerability found in the Linux kernel. The flaw resides within the `__ptrace_may_access()` function, which is part of the kernel's `ptrace` access-check logic. This vulnerability arises during the process exit sequence of privileged programs. Specifically, a brief window exists where the kernel releases a process's memory before closing its file descriptors. An unprivileged local user can exploit this timing window to intercept and read sensitive files that were opened by the privileged process, such as SSH host private keys or the contents of `/etc/shadow`.

Description: In the Linux kernel, the following vulnerability has been resolved: ptrace: slightly saner 'get_dumpable()' logic The 'dumpability' of a task is fundamentally about the memory image of the task - the concept comes from whether it can core dump or not - and makes no sense when you don't have an associated mm. And almost all users do in fact use it only for the case where the task has a mm pointer. But we have one odd special case: ptrace_may_access() uses 'dumpable' to check various other things entirely independently of the MM (typically explicitly using flags like PTRACE_MODE_READ_FSCREDS). Including for threads that no longer have a VM (and maybe never did, like most kernel threads). It's not what this flag was designed for, but it is what it is. The ptrace code does check that the uid/gid matches, so you do have to be uid-0 to see kernel thread details, but this means that the traditional "drop capabilities" model doesn't make any difference for this all. Make it all make a *bit* more sense by saying that if you don't have a MM pointer, we'll use a cached "last dumpability" flag if the thread ever had a MM (it will be zero for kernel threads since it is never set), and require a proper CAP_SYS_PTRACE capability to override.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status: Received

Risk scores

CVSS 3.1

Type: Secondary
Base score: 5.5
Impact score: 3.6
Exploitability score: 1.8
Vector string: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Severity: MEDIUM

Weaknesses

134c704f-9b21-4f2e-91b3-4a467353bcc0: CWE-269

Hype score: Not currently trending

References

Sources include official advisories and independent security research.