CVE-2026-88035
Description
A flaw was found in the MongoDB C Driver. This vulnerability, a heap buffer overflow, occurs in the client-side authentication process when handling unusually large usernames. An attacker who can control the driver's connection settings could exploit this to cause the application using the driver to crash, leading to a denial of service. Exploitation requires the optional external SASL (Simple Authentication and Security Layer) authentication backend to be enabled and configured.
Statement
This vulnerability is rated as Moderate severity because triggering the issue requires an application to use an optional external SASL authentication mechanism and allows an attacker with control over connection parameters to induce an application crash. In standard Red Hat environments, applications embedding the driver generally manage connection parameters within trusted boundaries rather than exposing them directly to arbitrary user input. The impact is strictly confined to a denial of service, with no compromise of data confidentiality or system integrity.
Mitigation
Mitigation: Fedora and EPEL users running mongo-c-driver are not affected as the shipped version 1.30.13 includes the fix introduced in version 1.30.10. Red Hat products do not ship the MongoDB C Driver and are not affected by this vulnerability.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided. If the calculated result involves time values, then the product might crash when it encounters a time that is less than the previously-calculated time.
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 overflow/wraparound 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 the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
Access Control
Technical Impact: Bypass Protection Mechanism; DoS: Crash, Exit, or Restart
If integer values are used in time-based, security-critical decisions, such as calculating expiration times or determining whether an event occurs within a specific time or date range, to cause an incorrect security decision. The consequences could even include "self-DoS" if the overflow produces a time value that is not accounted for in protection mechanism logic [REF-1570].
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
