CVE-2020-18032

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ModerateModerate ImpactWhat does this mean?

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Description

A flaw was found in graphviz. A wrong assumption in record_init function leads to an off-by-one write in parse_reclbl function, allowing an attacker who can provide graph input to potentially execute code when the label of a node is invalid and shorter than two characters. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

A flaw was found in graphviz. A wrong assumption in record_init function leads to an off-by-one write in parse_reclbl function, allowing an attacker who can provide graph input to potentially execute code when the label of a node is invalid and shorter than two characters. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Additional information

  • Bugzilla 1966272: graphviz: off-by-one in parse_reclbl() in lib/common/shapes.c
  • CWE-193: Off-by-one Error
  • FAQ: Frequently asked questions about CVE-2020-18032

Common Vulnerability Scoring System (CVSS) Score Details

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 HatNVD

CVSS v3 Base Score

7.8

7.8

Attack Vector

Local

Local

Attack Complexity

Low

Low

Privileges Required

None

None

User Interaction

Required

Required

Scope

Unchanged

Unchanged

Confidentiality Impact

High

High

Integrity Impact

High

High

Availability Impact

High

High

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Red Hat CVSS v3 Score Explanation

Impact set to Moderate due to the fact that graphviz is used only as a dependency of some short-lived program that would require a victim user to voluntarily use a malicious graphviz file.

Impact set to Moderate due to the fact that graphviz is used only as a dependency of some short-lived program that would require a victim user to voluntarily use a malicious graphviz file.

Understanding the Weakness (CWE)

CWE-193

Availability

Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Instability

This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.

Integrity

Technical Impact: Modify Memory

If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.

Confidentiality,Availability,Access Control

Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism

This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

What can I do if my product is listed as "Will not fix"?

What can I do if my product is listed as "Fix deferred"?

What is a mitigation?

I have a Red Hat product but it is not in the above list, is it affected?

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

My product is listed as "Out of Support Scope". What does this mean?

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