CVE-2026-33711
Description
A flaw was found in Incus, a system container and virtual machine manager. A local attacker could exploit a vulnerability in the API responsible for retrieving VM screenshots. By creating symbolic links (symlinks) in predictable temporary file paths, an attacker could trick Incus into truncating and altering arbitrary files on the filesystem. This could lead to a denial of service or, in specific configurations where the protected_symlinks kernel security feature is disabled, a local privilege escalation.
Statement
This Important flaw in Incus allows a local attacker to achieve denial of service or, under specific conditions, local privilege escalation. The vulnerability arises from predictable temporary file paths used during VM screenshot retrieval, enabling symlink attacks. On Red Hat Enterprise Linux, the protected_symlinks kernel security feature is enabled by default, which prevents the privilege escalation vector of this flaw.
Understanding the Weakness (CWE)
Confidentiality,Integrity,Access Control
Technical Impact: Read Files or Directories; Modify Files or Directories; Bypass Protection Mechanism
An attacker may be able to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. If the files are used for a security mechanism then an attacker may be able to bypass the mechanism.
Other
Technical Impact: Execute Unauthorized Code or Commands
Windows simple shortcuts, sometimes referred to as soft links, can be exploited remotely since a ".LNK" file can be uploaded like a normal file. This can enable remote execution.
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