CVE-2021-42785: glavsoft llc tightvnc viewer Classic Buffer Overflow
CVSS: 9.8v3.1CriticalModified
AliasesUBUNTU-CVE-2021-42785
Published 23-11-2021Last modified 04-08-2024
Vulnerability summary
CVE-2021-42785 is a critical (CVSS 9.8) Classic Buffer Overflow vulnerability in glavsoft llc tightvnc viewer. EPSS estimates a 2.34% chance of exploitation in the next 30 days, higher than 83.3% of scored vulnerabilities.
CVSS score
9.8/10
010
Critical · v3.1 (NVD)EPSS score
2.34%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 23-11-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.
CVSS metrics
3 scores · 2 sources · 2 versionsCritical 9.8Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 2 agree
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
High 7.5Preferred score · NVD (NIST)
AV:N/AC:L/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
2.34%
Chance of exploitation in the next 30 days
Percentile
83%
Versus all other CVEs
30-day change
0.00 pp
From 2.34% on 18-09-2026
18-09-202618-10-2026
EPSS score2.34%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Glavsoft llc1 product
- tightvnc viewer2.8.59
Tightvnc1 product
- tightvnc≤ 2.8.59
Ubuntu1 product
- tightvncAll versions (No fix recorded)
3 vendors · 3 products