CVE-2026-44307
Description
A flaw was found in Mako, a Python template library. A remote attacker could exploit a directory traversal vulnerability by crafting a Uniform Resource Identifier (URI) with backslash traversal. This bypasses security checks, allowing the attacker to read files outside the intended template directory, leading to information disclosure.
Statement
This flaw is rated Moderate (CVSS 5.9) because exploitation requires high attack complexity (AC:H) — the path traversal is Windows-specific and depends on attacker-controlled template names being passed to Mako's TemplateLookup. Red Hat products are deployed on Linux where this vulnerability is not exploitable, as Linux does not interpret backslash as a directory separator. The Resource Optimization Service ships the affected Mako version but runs on Linux, limiting practical impact.
Mitigation
This vulnerability is specific to Windows systems where backslash characters are interpreted as path separators. Red Hat products running on Linux are not susceptible to this path traversal because Linux does not treat backslash as a directory separator. For any application using Mako on Windows, validate user-controlled template names to reject backslash characters before passing them to TemplateLookup.get_template(). Upgrading to Mako 1.3.12 resolves this issue.
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 | 5.9 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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
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