CVE-2026-75804

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 enforces the stream-level but not the connection-level limit. To exploit the issue, three conditions must be met: - the remote peer opens several streams - each stream must stay within the stream-level flow control limit - there must be no zero-offset byte sent on any of the streams (to prevent the vulnerable QUIC stack from consuming data). By meeting the conditions above, the remote peer may make the local stack allocate 2 x MAX_STREAMS x (stream flow control limit) bytes of memory. MAX_STREAMS defaults to 100, and the limit applies to both bidirectional and unidirectional streams, making it 200 in total. The default flow control window for a stream is 512kB. The remote peer may force the vulnerable QUIC stack to allocate 100MB of heap per connection. FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.

• CWE-770

• https://github.com/openssl/openssl/commit/2e8f54666b3fb7b05ff5f58aa6cac9285163654ePatch
• https://github.com/openssl/openssl/commit/4533ee8a5686c953ed3b644738ac4bdf20806538Patch
• https://github.com/openssl/openssl/commit/64d3102fb5b54311e92517f26ba00169d719e74aPatch
• https://github.com/openssl/openssl/commit/f9eaecf5bdd6692da052bc65b0332af2a938ac03Patch
• https://openssl-library.org/news/secadv/20260929.txtVendor Advisory

Published

Sep 29, 2026

Last Modified

Oct 8, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-75798The AI Engine WordPress plugin before 3.7.2 does not perfor…5.3
• CVE-2026-75799The YAHMAN Add-ons WordPress plugin before 0.9.31 does not v…9
• CVE-2026-7580A vulnerability was detected in Exiftool up to 13.53. Impact…5.3
• CVE-2026-75800The Frontegg SAML SSO WordPress plugin through 1.0.1 does no…9.8
• CVE-2026-75802AjaxEditableChoiceLabel in wicket-extensions, when construct…5.4
• CVE-2026-75803Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with…9.1
• CVE-2026-75805Issue summary: A CMP client that requests certificate revoca…5.3
• CVE-2026-75806Issue summary: An established DTLS 1.2 association using an …5.3
• CVE-2026-75807The SAML Single Sign On – SSO Login plugin for WordPress is …7.5
• CVE-2026-75808Allocation of Resources Without Limits or Throttling in ASUS…5.7
• CVE-2026-75809Exposed IOCTL with insufficient access control in ASUS Armou…5.9
• CVE-2026-7581A security vulnerability has been detected in alexta69 MeTub…4.3