CVE-2026-30803: Integer Underflow (Wrap or Wraparound) vulnerability in RTI Connext Micro (Core Libraries) allows Overread Buffers.

Synopsis

An integer underflow (wrap-around) vulnerability in RTI Connext Micro's core libraries allows a remote, unauthenticated attacker to trigger an out-of-bounds buffer overread over the network. The vulnerability is reachable without any prior authentication or user interaction, as indicated by the CVSS v4.0 vector. Successful exploitation reads memory contents from the affected process and crashes the service, resulting in data disclosure and denial of availability. A patched-image rebuild at version 4.3.0 is available on HarborGuard for environments running an affected version (4.0.0 through before 4.3.0).

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The vulnerable service must be reachable over the network; an attacker sends crafted packets to trigger the integer underflow remotely (AV:N).

• AuthenticationNot required

  No credentials or session token are needed; the attack can be launched by any unauthenticated network peer (PR:N).

• Victim interactionNot required

  No user action is required; the attacker interacts directly with the service without any social-engineering step (UI:N).

• Attack complexityDetail

  The exploit is reliable and condition-free, requiring no race conditions, specific memory layout, or environmental pre-conditions (AC:L, AT:N).

Blast Radius

• An attacker reads memory contents from the Connext Micro process, which may include in-flight DDS messages, session state, or other data held in heap or stack buffers (VC:H).
• The overread crashes the affected Connext Micro service, terminating any real-time or embedded communication handled by that process (VA:H).
• Impact is confined to the vulnerable host; the CVSS v4.0 vector shows no confidentiality or availability impact on downstream or connected systems (SC:N, SA:N).