CVE-2026-39243
Description
A flaw was found in decompress. An attacker can craft a malicious archive that, when extracted, allows for arbitrary hardlink creation. This vulnerability occurs because the x.linkname field from hardlink entries in the archive is processed without proper validation, enabling an attacker to create a hardlink to any file on the same filesystem. This could lead to sensitive file read disclosure or file corruption on the system.
Statement
This Moderate flaw in the decompress library allows an attacker to create arbitrary hardlinks during archive extraction. By crafting a malicious archive, an attacker could exploit this to disclose sensitive file contents or corrupt files on the same filesystem where the archive is extracted. This risk is present in Red Hat products that utilize the decompress library for archive handling.
Upstream scores I:N, but Red Hat assigns I:L because a hardlink to an absolute path shares the target’s inode, so writes through the extracted name can corrupt or overwrite the original file, not only disclose its contents.
Mitigation
To mitigate this issue, avoid extracting archives from untrusted or unknown sources. When processing archives from potentially untrusted origins, consider using a sandboxed environment to limit the impact of any malicious content.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.1 | N/A | 5.5 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | Low | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
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.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
