---
id: "CVE-2026-58826"
kind: "vulnerability"
aliases: ["CVE-2026-58826"]
title: "Linux kernel: unshare use-after-free lets local user escalate privileges"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "linux-kernel", "multi-user-hosts", "self-hosted"]
not_affected_if: ["no-local-untrusted-users"]
published_at: "2026-11-02T20:17:47+00:00"
first_seen_at: "2026-11-02T20:35:30+00:00"
updated_at: "2026-11-02T20:39:09+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58826", "first_seen_at": "2026-11-02T20:35:30+00:00"}]
---

# Linux kernel: unshare use-after-free lets local user escalate privileges

A use-after-free in the kernel's ksys_unshare routine in fork.c corrupts memory. A local user with no extra privileges can use it to gain higher privileges on the system.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-11-02T20:35:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-58826

## From the sources

In ksys_unshare of fork.c, there is a possible memory corruption due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_