Heap-based buffer overflow in a regular-expression parser in Mozilla Network Security Services (NSS) before 3.12.3, as used in Firefox, Thunderbird, SeaMonkey, Evolution, Pidgin, and AOL Instant Messenger (AIM), allows remote SSL servers to cause a denial of service (application crash) or possibly execute arbitrary code via a long domain name in the subject's Common Name (CN) field of an X.509 certificate, related to the cert_TestHostName function.
Conclusion & alert: CVE-2009-2404 is rated Moderate Risk (63.5/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 4.15%). 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 | 21.02% | 4.15% | -16.87% |
| 2 | 2025-03-30 | 20.45% | 21.02% | +0.58% |
| 3 | 2025-03-29 | — | 20.45% | — |
Full EPSS history (11 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.3 | 2.0 | HIGH |
|
8.6 | 10.0 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
low | CVE-2009-2404 low priority: Debian including 1 source packages (nss), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2009-2404 |
gentoo
|
high | CVE-2009-2404: 1 GLSA(s) (201301-01), 14 atom(s) (dev-libs/nss, mail-client/mozilla-thunderbird, …); latest impact high. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2009-2404 |
redhat
|
critical | — | https://access.redhat.com/security/cve/CVE-2009-2404 |
ubuntu
|
medium | CVE-2009-2404 medium priority: Ubuntu including 1 source packages (nss), 5 status rows across 5 suites (dapper, hardy, intrepid, jaunty, upstream): released 3, DNE 1, needs-triage 1. | https://ubuntu.com/security/CVE-2009-2404 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mozilla | network_security_services | 3.12.3 | cpe:2.3:a:mozilla:network_security_services:3.12.3:*:*:*:*:*:*:* |