CVE-2020-25219
Description
A flaw was found in libproxy in versions 0.4 through 0.4.15. A remote HTTP server can trigger an uncontrolled recursion via a response composed of an infinite stream that lacks a newline character leading to a stack exhaustion. The highest threat from this vulnerability is to system availability.
Statement
Red Hat has determined this flaw to be of moderate impact as the attack triggers an uncontrolled recursion beyond the attacker's control and results in a DoS, which can cause service disruptions but does not directly enable privilege escalation or arbitrary code execution.
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 | 5.9 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
Successful exploitation requires that an attacker can provide a specially crafted response to a PAC request. This most likely means that it's from within the same network and possibly requires that another service is already under the attacker's control, thus access complexity has been set to high and access vector has been set to adjacent.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Resources including CPU, memory, and stack memory could be rapidly consumed or exhausted, eventually leading to an exit or crash.
Confidentiality
Technical Impact: Read Application Data
In some cases, an application's interpreter might kill a process or thread that appears to be consuming too much resources, such as with PHP's memory_limit setting. When the interpreter kills the process/thread, it might report an error containing detailed information such as the application's installation path.
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