The TLS stack in Mono before 3.12.1 allows man-in-the-middle attackers to conduct message skipping attacks and consequently impersonate clients by leveraging missing handshake state validation, aka a "SMACK SKIP-TLS" issue.
Conclusion & alert: CVE-2015-2318 is rated Moderate Risk (60.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.01%). 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 | 2026-06-15 | 1.29% | 2.01% | +0.72% |
| 2 | 2025-07-25 | 1.41% | 1.29% | -0.12% |
| 3 | 2025-03-30 | — | 1.41% | — |
Full EPSS history (13 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.1 | 3.0 | HIGH |
|
2.2 | 5.9 | [email protected] |
| 6.8 | 2.0 | MEDIUM |
|
8.6 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2015-2318 not yet assigned priority: Debian including 1 source packages (mono), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2015-2318 |
ubuntu
|
medium | CVE-2015-2318 medium priority: Ubuntu including 1 source packages (mono), 5 status rows across 5 suites (lucid, precise, trusty, upstream, utopic): released 4, ignored 1. | https://ubuntu.com/security/CVE-2015-2318 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mono-project | mono | < 3.12.1 | cpe:2.3:a:mono-project:mono:*:*:*:*:*:*:*:* |
| debian | debian_linux | 6.0 | cpe:2.3:o:debian:debian_linux:6.0:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| http://www.mono-project.com/news/2015/03/07/mono-tls-vulnerability/ | Vendor Advisory |
| http://www.openwall.com/lists/oss-security/2015/03/17/9 | Mailing List Third Party Advisory |
| http://www.securityfocus.com/bid/73253 | Third Party Advisory VDB Entry |
| http://www.ubuntu.com/usn/USN-2547-1 | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=1202869 | Issue Tracking Third Party Advisory |
| https://github.com/mono/mono/commit/1509226c41d74194c146deb173e752b8d3cdeec4 | Third Party Advisory |
| https://mitls.org/pages/attacks/SMACK#skip | Third Party Advisory |
| https://www.debian.org/security/2015/dsa-3202 | Third Party Advisory |