Quick answers
- Is CVE-2026-35191 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-35191 being exploited in the wild.
- How severe is CVE-2026-35191?
- Informational severity, published 29 September 2026.
- Which products and versions are affected?
- OpenSSL <UNKNOWN>.
- Is there a fix for CVE-2026-35191?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-35191 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-35191?
- Check whether you run OpenSSL at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
When the QUIC server operates without address validation (non-validation mode), it charges the entire datagram length against the unvalidated credit limit for each QUIC packet contained in that datagram, rather than once per datagram. An attacker can craft a single datagram containing multiple QUIC packets to artificially inflate the server's perception of received data, bypassing the RFC 9000-mandated 3x amplification limit until TLS handshake completion. This is a violation of expected behavior under RFC 9000 Section 8.
Affected products
- OpenSSL OpenSSL <UNKNOWN>
Timeline
- 2026-09-29: disclosed