CVE-2025-54574
Description
A heap-based buffer overflow flaw was found in the Squid caching proxy. When processing the Uniform Resource Name (URNs), specific conditions can lead to remote code execution.
Statement
This vulnerability is Important because the heap-based buffer overflow occurs during URN processing in Squid’s core request-handling path, which is exposed to untrusted, remote input. Unlike flaws that merely cause a service crash, this defect allows an attacker to manipulate heap memory structures, potentially achieving arbitrary code execution within the Squid process context. Since Squid often runs with elevated privileges and serves as a gateway between internal and external networks, successful exploitation could provide a remote attacker with direct control over the proxy server, enabling them to pivot into internal systems, intercept sensitive traffic, or alter cached content.
Mitigation
Users can disable URN access permissions to mitigate 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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.9 | 9.8 | 9.3 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Changed | Unchanged | Changed |
| Confidentiality | High | High | None |
| Integrity Impact | High | High | Low |
| Availability Impact | Low | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Integrity,Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Modify Memory
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. Besides important user data, heap-based overflows can be used to overwrite function pointers that may be living in memory, pointing it to the attacker's code. Even in applications that do not explicitly use function pointers, the run-time will usually leave many in memory. For example, object methods in C++ are generally implemented using function pointers. Even in C programs, there is often a global offset table used by the underlying runtime.
Integrity,Confidentiality,Availability,Access Control,Other
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Other
When the consequence is arbitrary code execution, this can often be used to subvert any other security service.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
