The pstm_reverse function in MatrixSSL before 3.8.4 allows remote attackers to cause a denial of service (invalid memory read and crash) via a (1) zero value or (2) the key's modulus for the secret key during RSA key exchange.
Conclusion & alert: CVE-2016-6886 is rated Moderate Risk (55.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.81%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-03-30 | 0.89% | 0.81% | -0.07% |
| 2 | 2025-03-29 | 0.81% | 0.89% | +0.07% |
| 3 | 2025-03-17 | — | 0.81% | — |
Full EPSS history (6 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.0 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
ubuntu
|
low | CVE-2016-6886 low priority: Ubuntu including 1 source packages (matrixssl), 10 status rows across 10 suites (artful, bionic, cosmic, disco, precise, trusty, upstream, xenial, yakkety, zesty): DNE 8, ignored 1, released 1. | https://ubuntu.com/security/CVE-2016-6886 |
| URL | Tags |
|---|---|
| http://www.matrixssl.org/blog/releases/matrixssl_3_8_4 | Patch Vendor Advisory |
| http://www.securityfocus.com/bid/92604 | |
| https://blog.fuzzing-project.org/51-Fun-with-Bignums-Crashing-MatrixSSL-and-more.html | Third Party Advisory |