Integer underflow in Sandstorm Cap'n Proto before 0.4.1.1 and 0.5.x before 0.5.1.1 might allow remote peers to cause a denial of service or possibly obtain sensitive information from memory or execute arbitrary code via a crafted message.
Conclusion & alert: CVE-2015-2311 is rated High Risk (66/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.98%). Mandatory action: High exploitation likelihood—assess exposure and prioritize 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 | 2026-04-12 | 1.05% | 0.98% | -0.07% |
| 2 | 2025-03-30 | 2.92% | 1.05% | -1.86% |
| 3 | 2025-03-29 | — | 2.92% | — |
Full EPSS history (9 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2015-2311 not yet assigned priority: Debian including 1 source packages (capnproto), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2015-2311 |
ubuntu
|
medium | CVE-2015-2311 medium priority: Ubuntu including 1 source packages (capnproto), 10 status rows across 10 suites (artful, bionic, lucid, precise, trusty, upstream, wily, xenial, yakkety, zesty): not-affected 5, DNE 2, released 2, ignored 1. | https://ubuntu.com/security/CVE-2015-2311 |
| URL | Tags |
|---|---|
| http://www.openwall.com/lists/oss-security/2015/03/17/3 | Mailing List Third Party Advisory |
| https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=780566 | Mailing List Third Party Advisory |
| https://github.com/capnproto/capnproto/blob/master/security-advisories/2015-03-02-1-c%2B%2B-integer-underflow.md | Third Party Advisory |
| https://github.com/capnproto/capnproto/commit/26bcceda72372211063d62aab7e45665faa83633 | Third Party Advisory |