CVE-2002-1336

TightVNC before 1.2.6 generates the same challenge string for multiple connections, which allows remote attackers to bypass VNC authentication by sniffing the challenge and response of other users.

Published: 2002-12-11 Last update: 2026-04-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2002-1336 is rated Moderate Risk (56.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.07%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2002-1336

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 2025-07-27 1.30% 1.07% -0.22%
2 2025-03-17 0.46% 1.30% +0.84%
3 2023-08-09 — 0.46% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2002-1336

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2002-1336

OS Trackers for CVE-2002-1336

vendor priority summary link
debian not yet assigned CVE-2002-1336 not yet assigned priority: Debian including 1 source packages (tightvnc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2002-1336
redhat medium — https://access.redhat.com/security/cve/CVE-2002-1336

Affected software / configurations for CVE-2002-1336

Vendor Product Version Raw CPE
tightvnc tightvnc 1.2.0 cpe:2.3:a:tightvnc:tightvnc:1.2.0:*:*:*:*:*:*:*
tightvnc tightvnc 1.2.1 cpe:2.3:a:tightvnc:tightvnc:1.2.1:*:*:*:*:*:*:*
tightvnc tightvnc 1.2.3 cpe:2.3:a:tightvnc:tightvnc:1.2.3:*:*:*:*:*:*:*
tightvnc tightvnc 1.2.4 cpe:2.3:a:tightvnc:tightvnc:1.2.4:*:*:*:*:*:*:*
tightvnc tightvnc 1.2.5 cpe:2.3:a:tightvnc:tightvnc:1.2.5:*:*:*:*:*:*:*

References for CVE-2002-1336

cvelogic Threat Intelligence