# CVE-2026-11999 — wolfSSL

> As of 2026-06-25, CVE-2026-11999 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in wolfSSL, CVSS v4.0 8.2, EPSS 0.2% (13.1th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-11999, most recently “Multiple WolfSSL Critical Vulnerabilities: Certificate Bypass, RCE, and Post-Quantum Weakening”.

**Last updated:** 2026-06-25

## What is CVE-2026-11999?

X.509 trust-chain bypass (path-depth exhaustion) in the OpenSSL compatibility certificate verifier (wolfSSL_X509_verify_cert()). This affects only builds with --enable-opensslextra whose application calls X509_verify_cert() with caller-supplied untrusted intermediates; for those users it is critical, otherwise the library is unaffected. Native wolfSSL TLS/DTLS usage is not impacted. X509_verify_cert() returned success based only on the last verified link rather than on reaching a trust anchor: when the supplied chain is deeper than the verifier's maximum path depth (default 100), path building runs out of depth while still walking untrusted intermediates and the chain is accepted even though it never reaches a configured trust anchor, allowing acceptance of an attacker-controlled certificate. The default TLS handshake (WOLFSSL_VERIFY_PEER) is not affected; only applications doing manual or deferred verification through this API are.

The record classifies CVE-2026-11999 under weakness class [CWE-295](https://intel.threadlinqs.com/cwe/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

## Is CVE-2026-11999 being exploited?

Weaponised exploit code for CVE-2026-11999 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](https://github.com/trickest/cve/blob/main/2026/CVE-2026-11999.md) (trickest)

## Affected products and versions

- [wolfSSL](https://intel.threadlinqs.com/vendors/wolfssl): wolfSSL

## How to fix CVE-2026-11999

No vendor patch reference has been recorded for CVE-2026-11999 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-2026-11999

1 tracked threat in the Threadlinqs corpus references CVE-2026-11999, 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](https://intel.threadlinqs.com/threat/TL-2026-1008) — CRITICAL · 2026-06-30

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/wolfSSL/wolfssl/pull/10674)

**Other references**

- [wolfssl.com](https://www.wolfssl.com/docs/security-vulnerabilities/)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-11999
Full detection coverage and IOCs for threats exploiting CVE-2026-11999 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp