The CMsgReader::readRect function in the VNC Viewer component in RealVNC VNC Free Edition 4.0 through 4.1.2, Enterprise Edition E4.0 through E4.4.2, and Personal Edition P4.0 through P4.4.2 allows remote VNC servers to execute arbitrary code via crafted RFB protocol data, related to "encoding type."
Conclusion & alert: CVE-2008-4770 is rated High Risk (70.3/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 4.74%). 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 | 2026-06-08 | 5.82% | 4.74% | -1.08% |
| 2 | 2025-06-15 | 8.62% | 5.82% | -2.80% |
| 3 | 2025-03-30 | — | 8.62% | — |
Full EPSS history (10 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 10.0 | 2.0 | HIGH |
|
10.0 | 10.0 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
gentoo
|
normal | CVE-2008-4770: 1 GLSA(s) (200903-17), 1 atom(s) (net-misc/vnc); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2008-4770 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2008-4770 |
ubuntu
|
medium | CVE-2008-4770 medium priority: Ubuntu including 1 source packages (vnc4), 11 status rows across 11 suites (dapper, gutsy, hardy, intrepid, jaunty, karmic, lucid, maverick, natty, oneiric, upstream): ignored 6, not-affected 4, released 1. | https://ubuntu.com/security/CVE-2008-4770 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| realvnc | realvnc | 4.0 | cpe:2.3:a:realvnc:realvnc:4.0:*:free:*:*:*:*:* |
| realvnc | realvnc | 4.1.2 | cpe:2.3:a:realvnc:realvnc:4.1.2:*:free:*:*:*:*:* |
| realvnc | realvnc | 4.4.2 | cpe:2.3:a:realvnc:realvnc:4.4.2:*:enterprise:*:*:*:*:* |
| realvnc | realvnc | e4.0 | cpe:2.3:a:realvnc:realvnc:e4.0:*:enterprise:*:*:*:*:* |
| realvnc | realvnc | p4.0 | cpe:2.3:a:realvnc:realvnc:p4.0:*:personal:*:*:*:*:* |
| realvnc | realvnc | p4.4.2 | cpe:2.3:a:realvnc:realvnc:p4.4.2:*:personal:*:*:*:*:* |