Quick answers
- Is CVE-2026-42772 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-42772 being exploited in the wild.
- How severe is CVE-2026-42772?
- Informational severity, published 29 September 2026.
- Which products and versions are affected?
- OpenSSL Versions with QUIC support prior to fix (2026-09-26).
- Is there a fix for CVE-2026-42772?
- A patch was published on 2026-09-26: Fix merged in OpenSSL repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-42772 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-42772?
- 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
The QUIC stream reassembly algorithm uses a doubly-linked list that falls back to head-to-tail linear search for fragments not at the list's end, resulting in O(n²) complexity when an attacker manipulates packet offset sequences. An authenticated remote QUIC peer can trigger this by sending compliant STREAM frames within the advertised receive window. A fix has been implemented using a red-black tree-based approach with O(log n) lookup complexity.
Affected products
- OpenSSL OpenSSL Versions with QUIC support prior to fix (2026-09-26)
Timeline
- 2026-09-29: disclosed: CVE-2026-42772 published
- 2026-09-26: patched: Fix merged in OpenSSL repository