CVE-2026-75804

/// Technical description

Issue summary: OpenSSL QUIC stack does not enforce connection

level flow control for streams. Remote peers may send more bytes

as long as they fit within the stream flow control limits.

Impact summary: A malicious remote peer may exploit the lack of connection

flow control for streams to make the QUIC stack receive ~100MB of memory

instead of 768 KiB (default flow control window size).

CWE: CWE-770: Allocation of Resources Without Limits or Throttling

Description: The local QUIC stack advertises two flow control limits

to its remote peer: stream flow control limit and connection flow

control limit. The remote peer must follow both limits when transmitting

stream data.

Whenever the local QUIC stack receives a stream frame, it validates

that the size of the received stream frame stays within flow control limits.

If either limit is exceeded (stream level or connection level), then

the QUIC stack must close the connection with a flow control error.

The vulnerable OpenSSL QUIC stack en

/// Remediation

Check the references section for vendor advisories and patches from openssl. Update openssl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// Affected products

/// References