socket.c in fetchmail before 6.3.11 does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.
Conclusion & alert: CVE-2009-2666 is rated Moderate Risk (51.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.50%). 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 | 0.66% | 1.50% | +0.84% |
| 2 | 2025-12-01 | 0.58% | 0.66% | +0.08% |
| 3 | 2025-03-30 | — | 0.58% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.4 | 2.0 | MEDIUM |
|
10.0 | 4.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2009-2666 not yet assigned priority: Debian including 1 source packages (fetchmail), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2009-2666 |
gentoo
|
normal | CVE-2009-2666: 1 GLSA(s) (201006-12), 1 atom(s) (net-mail/fetchmail); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2009-2666 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2009-2666 |
suse
|
medium | CVE-2009-2666 severity moderate: SUSE including 15 source package names (fetchmail-6.3.26-12.3, fetchmail-6.3.26-13.4, …), 44 product×package rows across 28 product lines (SUSE Linux Enterprise Desktop 12, SUSE Linux Enterprise Desktop 12 SP1, … (28 product lines)): Fixed 44. | https://www.suse.com/security/cve/CVE-2009-2666/ |
ubuntu
|
medium | CVE-2009-2666 medium priority: Ubuntu including 1 source packages (fetchmail), 5 status rows across 5 suites (dapper, hardy, intrepid, jaunty, upstream): released 4, needs-triage 1. | https://ubuntu.com/security/CVE-2009-2666 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| fetchmail | fetchmail | <= 6.3.10 | cpe:2.3:a:fetchmail:fetchmail:*:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.1 | cpe:2.3:a:fetchmail:fetchmail:4.5.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.2 | cpe:2.3:a:fetchmail:fetchmail:4.5.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.3 | cpe:2.3:a:fetchmail:fetchmail:4.5.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.4 | cpe:2.3:a:fetchmail:fetchmail:4.5.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.5 | cpe:2.3:a:fetchmail:fetchmail:4.5.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.6 | cpe:2.3:a:fetchmail:fetchmail:4.5.6:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.7 | cpe:2.3:a:fetchmail:fetchmail:4.5.7:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.5.8 | cpe:2.3:a:fetchmail:fetchmail:4.5.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.0 | cpe:2.3:a:fetchmail:fetchmail:4.6.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.1 | cpe:2.3:a:fetchmail:fetchmail:4.6.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.2 | cpe:2.3:a:fetchmail:fetchmail:4.6.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.3 | cpe:2.3:a:fetchmail:fetchmail:4.6.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.4 | cpe:2.3:a:fetchmail:fetchmail:4.6.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.5 | cpe:2.3:a:fetchmail:fetchmail:4.6.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.6 | cpe:2.3:a:fetchmail:fetchmail:4.6.6:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.7 | cpe:2.3:a:fetchmail:fetchmail:4.6.7:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.8 | cpe:2.3:a:fetchmail:fetchmail:4.6.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.6.9 | cpe:2.3:a:fetchmail:fetchmail:4.6.9:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.0 | cpe:2.3:a:fetchmail:fetchmail:4.7.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.1 | cpe:2.3:a:fetchmail:fetchmail:4.7.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.2 | cpe:2.3:a:fetchmail:fetchmail:4.7.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.3 | cpe:2.3:a:fetchmail:fetchmail:4.7.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.4 | cpe:2.3:a:fetchmail:fetchmail:4.7.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.5 | cpe:2.3:a:fetchmail:fetchmail:4.7.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.6 | cpe:2.3:a:fetchmail:fetchmail:4.7.6:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 4.7.7 | cpe:2.3:a:fetchmail:fetchmail:4.7.7:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.0 | cpe:2.3:a:fetchmail:fetchmail:5.0.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.1 | cpe:2.3:a:fetchmail:fetchmail:5.0.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.2 | cpe:2.3:a:fetchmail:fetchmail:5.0.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.3 | cpe:2.3:a:fetchmail:fetchmail:5.0.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.4 | cpe:2.3:a:fetchmail:fetchmail:5.0.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.5 | cpe:2.3:a:fetchmail:fetchmail:5.0.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.6 | cpe:2.3:a:fetchmail:fetchmail:5.0.6:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.7 | cpe:2.3:a:fetchmail:fetchmail:5.0.7:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.0.8 | cpe:2.3:a:fetchmail:fetchmail:5.0.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.1.0 | cpe:2.3:a:fetchmail:fetchmail:5.1.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.1.4 | cpe:2.3:a:fetchmail:fetchmail:5.1.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.2.0 | cpe:2.3:a:fetchmail:fetchmail:5.2.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.2.1 | cpe:2.3:a:fetchmail:fetchmail:5.2.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.2.3 | cpe:2.3:a:fetchmail:fetchmail:5.2.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.2.4 | cpe:2.3:a:fetchmail:fetchmail:5.2.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.2.7 | cpe:2.3:a:fetchmail:fetchmail:5.2.7:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.2.8 | cpe:2.3:a:fetchmail:fetchmail:5.2.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.3.0 | cpe:2.3:a:fetchmail:fetchmail:5.3.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.3.1 | cpe:2.3:a:fetchmail:fetchmail:5.3.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.3.3 | cpe:2.3:a:fetchmail:fetchmail:5.3.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.3.8 | cpe:2.3:a:fetchmail:fetchmail:5.3.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.4.0 | cpe:2.3:a:fetchmail:fetchmail:5.4.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.4.3 | cpe:2.3:a:fetchmail:fetchmail:5.4.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.4.4 | cpe:2.3:a:fetchmail:fetchmail:5.4.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.4.5 | cpe:2.3:a:fetchmail:fetchmail:5.4.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.5.0 | cpe:2.3:a:fetchmail:fetchmail:5.5.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.5.2 | cpe:2.3:a:fetchmail:fetchmail:5.5.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.5.3 | cpe:2.3:a:fetchmail:fetchmail:5.5.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.5.5 | cpe:2.3:a:fetchmail:fetchmail:5.5.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.5.6 | cpe:2.3:a:fetchmail:fetchmail:5.5.6:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.6.0 | cpe:2.3:a:fetchmail:fetchmail:5.6.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.7.0 | cpe:2.3:a:fetchmail:fetchmail:5.7.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.7.2 | cpe:2.3:a:fetchmail:fetchmail:5.7.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.7.4 | cpe:2.3:a:fetchmail:fetchmail:5.7.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8 | cpe:2.3:a:fetchmail:fetchmail:5.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.1 | cpe:2.3:a:fetchmail:fetchmail:5.8.1:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.2 | cpe:2.3:a:fetchmail:fetchmail:5.8.2:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.3 | cpe:2.3:a:fetchmail:fetchmail:5.8.3:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.4 | cpe:2.3:a:fetchmail:fetchmail:5.8.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.5 | cpe:2.3:a:fetchmail:fetchmail:5.8.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.6 | cpe:2.3:a:fetchmail:fetchmail:5.8.6:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.11 | cpe:2.3:a:fetchmail:fetchmail:5.8.11:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.13 | cpe:2.3:a:fetchmail:fetchmail:5.8.13:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.14 | cpe:2.3:a:fetchmail:fetchmail:5.8.14:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.8.17 | cpe:2.3:a:fetchmail:fetchmail:5.8.17:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.0 | cpe:2.3:a:fetchmail:fetchmail:5.9.0:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.4 | cpe:2.3:a:fetchmail:fetchmail:5.9.4:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.5 | cpe:2.3:a:fetchmail:fetchmail:5.9.5:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.8 | cpe:2.3:a:fetchmail:fetchmail:5.9.8:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.10 | cpe:2.3:a:fetchmail:fetchmail:5.9.10:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.11 | cpe:2.3:a:fetchmail:fetchmail:5.9.11:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 5.9.13 | cpe:2.3:a:fetchmail:fetchmail:5.9.13:*:*:*:*:*:*:* |
| fetchmail | fetchmail | 6.0.0 | cpe:2.3:a:fetchmail:fetchmail:6.0.0:*:*:*:*:*:*:* |