CVE-2026-28497: maximmasiutin tinyweb Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-28497 is a critical (CVSS 9.3) Integer Overflow or Wraparound vulnerability in maximmasiutin tinyweb. EPSS estimates a 0.69% chance of exploitation in the next 30 days, higher than 52% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 06-03-2026
   PublishedVulnerability first disclosed.
2. 06-03-2026
   Last modifiedVulnerability information updated.

Description

TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. Prior to version 2.03, an integer overflow vulnerability in the string-to-integer conversion routine (_Val) allows an unauthenticated remote attacker to bypass Content-Length restrictions and perform HTTP Request Smuggling. This can lead to unauthorized access, security filter bypass, and potential cache poisoning. The impact is critical for servers using persistent connections (Keep-Alive). This issue has been patched in version 2.03.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.