CVE-2019-17190
A Local Privilege Escalation issue was discovered in Avast Secure Browser 76.0.1659.101.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.52%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A Local Privilege Escalation issue was discovered in Avast Secure Browser 76.0.1659.101. The vulnerability is due to an insecure ACL set by the AvastBrowserUpdate.exe (which is running as NT AUTHORITY\SYSTEM) when AvastSecureBrowser.exe checks for new updates. When the update check is triggered, the elevated process cleans the ACL of the Update.ini file in %PROGRAMDATA%\Avast Software\Browser\Update\ and sets all privileges to group Everyone. Because any low-privileged user can create, delete, or modify the Update.ini file stored in this location, an attacker with low privileges can create a hard link named Update.ini in this folder, and make it point to a file writable by NT AUTHORITY\SYSTEM. Once AvastBrowserUpdate.exe is triggered by the update check functionality, the DACL is set to a misconfigured value on the crafted Update.ini and, consequently, to the target file that was previously not writable by the low-privileged attacker.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.52% probability · 44th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-863
- Affected
- avast/secure browser
- Source
- cve@mitre.org
EPSS 0.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://packetstormsecurity.com/files/156844/Avast-Secure-Browser-76.0.1659.101-Local-Privilege-Escalation.htmlThird Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2020/Mar/25Mailing List, Third Party Advisory
- https://www.avast.com/bug-bounty-credits/en/a-tribute-to-our-security-research-communityVendor Advisory
- http://packetstormsecurity.com/files/156844/Avast-Secure-Browser-76.0.1659.101-Local-Privilege-Escalation.htmlThird Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2020/Mar/25Mailing List, Third Party Advisory
- https://www.avast.com/bug-bounty-credits/en/a-tribute-to-our-security-research-communityVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.