CVE-2021-45339: avast antivirus Incorrect Authorization
CVSS: 7.8v3.1HighModified
Published 27-12-2021Last modified 04-08-2024
Vulnerability summary
CVE-2021-45339 is a high (CVSS 7.8) Incorrect Authorization vulnerability in avast antivirus. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.3% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
7.8/10
010
High · v3.1 (NVD)EPSS score
0.33%
0%100%
Low · +0.01 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github
Timeline
- 27-12-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Privilege escalation vulnerability in Avast Antivirus prior to 20.4 allows a local user to gain elevated privileges by "hollowing" trusted process which could lead to the bypassing of Avast self-defense.
CVSS metrics
2 scores · 1 source · 2 versionsHigh 7.8Preferred score · NVD (NIST)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSourcesSingle source
High 7.2Preferred score · NVD (NIST)
AV:L/AC:L/Au:N/C:C/I:C/A:CSourcesSingle source
EPSS trend
Probability
0.33%
Chance of exploitation in the next 30 days
Percentile
24%
Versus all other CVEs
30-day change
+0.01 pp
From 0.32% on 20-09-2026
20-09-202620-10-2026
EPSS score0.33%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundVulnerability Disclosures
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Avast1 product
- antivirus< 20.4
1 vendor · 1 product
References
2 links- www.avast.com/hacker-hall-of-fame/en/researcher-david-eade-reports-antitrack-bug-to-avast-0X Refsource MISCVendor Advisory
- github.com/the-deniss/Vulnerability-Disclosures/tree/main/CVE-2021-AVST0X Refsource MISCExploitThird Party Advisory