What is CVE-2026-55960?
Un-negotiated Raw Public Key (RFC 7250) accepted in place of an X.509 certificate, bypassing chain validation. A raw public key has no chain, so ParseCertRelative() accepts it without performing any trust verification; it must therefore only be accepted when RPK was actually negotiated for that peer. The check now defaults the expected type to X.509 (per RFC 7250/8446) when no type was negotiated, comparing against the received server certificate type on the client and the selected client certificate type on the server, and rejects any mismatch, including an un-negotiated raw public key, with UNSUPPORTED_CERTIFICATE. Only affects builds with Raw Public Key support (HAVE_RPK) enabled - disabled by default in a standalone build, but included in --enable-all.
The record classifies CVE-2026-55960 under weakness class CWE-295. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 107 days ago.
Severity and exploitation probability
- CVSS v4.0 base score
- 8.2 — High (derived from score)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - EPSS (FIRST)
- 0.2% probability of exploitation in the next 30 days, higher than 13.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-06-25, last modified 2026-06-26
Is CVE-2026-55960 being exploited?
Weaponised exploit code for CVE-2026-55960 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 20 in the Threadlinqs vulnerability feed.
- trickest/cve (trickest)
Affected products and versions
- wolfSSL: wolfSSL
How to fix CVE-2026-55960
No vendor patch reference has been recorded for CVE-2026-55960 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-55960
1 tracked threat in the Threadlinqs corpus references CVE-2026-55960, either in the campaign’s CVE list or as an indicator on the campaign record.
- Multiple WolfSSL Critical Vulnerabilities: Certificate Bypass, RCE, and Post-Quantum Weakening — CRITICAL · 2026-06-30
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on .