Allocation of Resources Without Limits or Throttling in OpenSSL - CVE-2026-84784
Published: September 30, 2026
Vulnerability identifier: #VU152964
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84784
CWE-ID: CWE-770
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to allocation of resources without limits or throttling in the QUIC RETIRE_CONNECTION_ID control frame queue when processing NEW_CONNECTION_ID frames without acknowledgements. A remote attacker can flood the connection with NEW_CONNECTION_ID frames and withhold acknowledgements to cause a denial of service.
The backlog consists of queued RETIRE_CONNECTION_ID control frames.
Affected software
OpenSSL
Debian Linux
openssl (Debian package)
Debian Linux
openssl (Debian package)
How to mitigate CVE-2026-84784
Install security update from vendor's website.
OpenSSL - addressed in versions 1.0.2zs, 1.1.1zj, 3.0.23, 3.4.8, 3.5.9, 3.6.5, 4.0.3
openssl (Debian package) - update to 3.5.7-1~deb13u3
openssl (Debian package) - update to 3.5.7-1~deb13u3