CVE-2026-115473
Description
A flaw was found in Mongoose. Due to missing length validation during path sanitization, an unauthenticated remote attacker can trigger a heap out-of-bounds read by sending specially crafted HTTP requests with malformed short paths. This allows the application to read memory beyond allocated buffer boundaries, which may lead to a denial of service (DoS) by causing the service to crash, or result in information disclosure.
Statement
This vulnerability is evaluated as Moderate severity because it is constrained to localized denial of service or minor memory disclosure, without enabling arbitrary code execution or state modification. In standard Linux deployment environments, process-level virtual memory protections limit the blast radius of a single-byte read beyond buffer bounds, typically causing a crash only if an unmapped page boundary is crossed. Furthermore, exposure is contingent upon an application specifically serving directory contents or handling file uploads over untrusted network interfaces.
Mitigation
Limit network access to applications embedding Mongoose by restricting exposure to trusted networks or localhost using firewall rules, and avoid exposing directory listing or file upload handlers to untrusted clients.
To restrict incoming traffic on the application port using firewalld:
1. Allow access only from trusted IP addresses or subnets:
firewall-cmd --permanent --zone=public --add-rich-rule='rule family="ipv4" source address="<trusted_ip_or_subnet>" port port="<port>" protocol="tcp" accept'
2. Apply the firewall configuration:
firewall-cmd --reload
Caveats: Restricting network traffic will prevent unauthenticated external clients from reaching the service. Reloading firewalld may temporarily disrupt active network sessions.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
