CVE-2019-10691

Public on

Last Modified: UTC

Description

The CVE Program describes this issue as:

The JSON encoder in Dovecot before 2.3.5.2 allows attackers to repeatedly crash the authentication service by attempting to authenticate with an invalid UTF-8 sequence as the username.

Statement

A flaw was found in the JSON encoder in dovecot, which an attacker could use to crash the application via usage of invalid UTF-8 characters in the login name during authentication or by using invalid UTF-8 sequence in email when OX push notification driver is enabled. The versions of dovecot shipped with Red Hat Enterprise Linux did not ship the vulnerable code and therefore were not affected by this flaw.

A flaw was found in the JSON encoder in dovecot, which an attacker could use to crash the application via usage of invalid UTF-8 characters in the login name during authentication or by using invalid UTF-8 sequence in email when OX push notification driver is enabled. The versions of dovecot shipped with Red Hat Enterprise Linux did not ship the vulnerable code and therefore were not affected by this flaw.

Additional information

  • Bugzilla 1701216: dovecot: Mishandling invalid UTF-8 characters by JSON encoder leading to possible DoS attack.
  • CWE-228: Improper Handling of Syntactically Invalid Structure
  • FAQ: Frequently asked questions about CVE-2019-10691

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).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

7.5

7.5

Attack Vector

Network

Network

Attack Complexity

Low

Low

Privileges Required

None

None

User Interaction

None

None

Scope

Unchanged

Unchanged

Confidentiality Impact

None

None

Integrity Impact

None

None

Availability Impact

High

High

CVSS v3 Vector

Red Hat: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Understanding the Weakness (CWE)

CWE-228

Integrity,Availability

Technical Impact: Unexpected State; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)

If an input is syntactically invalid, then processing the input could place the system in an unexpected state that could lead to a crash, consume available system resources or other unintended behaviors.

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?

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