{"id":"UBUNTU-CVE-2026-63075","details":"Issue summary: When OpenSSL processes QUIC traffic from a peer that repeatedly sends ack-eliciting packets while not acknowledging ACK-only responses, the QUIC stack can retain ACK-only packet metadata for the lifetime of the connection. Impact summary: A remote peer that can complete a QUIC handshake can cause connection-scoped memory growth which may lead to Denial of Service through memory exhaustion, especially with sustained traffic or many concurrent QUIC connections. CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: When the OpenSSL QUIC stack sends an ACK-only packet, there is no requirement by the QUIC protocol that the peer will acknowledge that ACK-only packet (i.e. it is itself not ack-eliciting). However, the OpenSSL implementation stores the metadata about the ACK frames regardless. In and of itself that's ok, but if a malicious peer establishes a connection, and then drives the connection such that ACK-only packets are forced from the OpenSSL implementation peer (i.e., by sending numerous PING frames), and then withholding any subsequent acks for ack-eliciting data, like legitimate data, said malicious peer can force inappropriate memory growth on the OpenSSL peer, potentially leading to a Denial of Service. The fix is to ensure that we account for the transmission of the ACK-only packet in the packet histories high and low watermark without actually storing the ACK-only packet metadata itself. FIPS impact: no The OpenSSL FIPS module is not affected as the QUIC code is outside the FIPS module boundary.","modified":"2026-09-16T14:01:40.960504470Z","published":"2026-08-25T00:00:00Z","related":["USN-8678-1"],"upstream":["CVE-2026-63075"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-63075"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-63075"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8678-1"}],"affected":[{"package":{"name":"nodejs","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.10.25~dfsg2-2ubuntu1","4.2.2~dfsg-1","4.2.3~dfsg-1","4.2.4~dfsg-1ubuntu1","4.2.4~dfsg-2","4.2.6~dfsg-1ubuntu1","4.2.6~dfsg-1ubuntu4","4.2.6~dfsg-1ubuntu4.1","4.2.6~dfsg-1ubuntu4.2","4.2.6~dfsg-1ubuntu4.2+esm1","4.2.6~dfsg-1ubuntu4.2+esm2","4.2.6~dfsg-1ubuntu4.2+esm3"],"ecosystem_specific":{"priority_reason":"OpenSSL developers have rated this low 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