CVE-2026-57966
Description
A path traversal vulnerability was found in spice-vdagent. This flaw allows a malicious or compromised SPICE host to write arbitrary files to any location on the guest operating system. This occurs because the filename provided by the SPICE host during file transfers is not properly sanitized before being used. An attacker could exploit this to write to sensitive locations with the privileges of the spice-vdagent process, typically the logged-in user. This issue requires the SPICE host to be untrusted or compromised for exploitation.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | N/A | 4.4 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | High | N/A | High |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Red Hat CVSS v3 Score Explanation
Requires a malicious or compromised SPICE host (PR:H) to send a file transfer with a crafted filename containing absolute path or '..' traversal. g_build_filename() silently discards save_dir for absolute paths. Allows arbitrary file write on the guest filesystem as the spice-vdagent user. I:H because the attacker can write to sensitive locations (e.g., ~/.ssh/authorized_keys, ~/.bashrc, /etc/cron.d/). Distinct from CVE-2017-15108 which was command injection via save_dir, not path traversal via filename.
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity
Technical Impact: Modify Files or Directories
The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality
Technical Impact: Read Files or Directories
The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of protection mechanisms such as authentication, it has the potential to lock out product users.
Acknowledgements
Red Hat would like to thank Ashish Kunwar for reporting this issue.
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