CVE-2026-54873

Issue summary: QUIC process may keep memory for QUIC packet

buffer for much longer period than necessary.

Impact summary: Remote peer can exploit this vulnerability

by sending maliciously crafted packets, making the local

QUIC stack to keep the memory for packet buffers allocated.

The time for which the memory remains allocated is entirely

under the control of the potentially malicious remote peer.

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

Description: To save copy operation from the packet buffer to the

stream reassemble buffer the QUIC stack leaves the stream data

on the packet buffer waiting to be copied to a buffer provided

by the local receiving application. The QUIC stack releases

a reference to the packet buffer only after the data are copied

to the application buffer. This design is more efficient for

legitimate data transfers but enables an attacker to allocate a lot

more memory than actually required by the data kept in the receiving

stream buffer.

To mitigate the vulnerability, the QUIC stack now calculates

and monitors memory overhead for every stream. The memory overhead

for a single stream frame is calculated as a difference between the

size of the whole packet that carries the stream frame and the size

of the stream frame itself. The memory overhead for a single stream

frame is added to the total (cumulative) memory overhead QUIC stack

keeps for each stream. Once the cumulative memory overhead exceeds

64kB, the QUIC stack moves the stream frame data from the packet

buffer to the stream buffer, starting with the next packet received.

FIPS impact: no

The FIPS module is not affected as the QUIC implementation is outside of

the OpenSSL FIPS module boundary.