Platform
linux
Component
threaded-usenet-news-reader
Fixed in
3.6.1
CVE-2016-20042 describes a stack buffer overflow vulnerability found in Threaded USENET News Reader. This flaw allows a local attacker to execute arbitrary code by crafting a malicious command-line argument. The vulnerability affects version 3.6-23. A fix is available via updated versions of the software.
Successful exploitation of CVE-2016-20042 allows an attacker with local access to the system to gain complete control. By providing an oversized argument (specifically, 156 bytes of padding followed by a return address), the attacker can overwrite the instruction pointer and execute their own shellcode. This effectively grants them arbitrary code execution privileges with the user account under which Threaded USENET News Reader is running. The potential impact includes data theft, system compromise, and potentially, lateral movement within the network if the affected user has elevated privileges.
CVE-2016-20042 was published on 2026-03-28. There is no indication of active exploitation or inclusion in the CISA KEV catalog. Public proof-of-concept exploits are not widely available, but the vulnerability's nature (stack buffer overflow) makes it relatively straightforward to develop an exploit. The vulnerability's local access requirement limits its immediate exploitability in widespread campaigns.
Exploit Status
EPSS
0.02% (4% percentile)
CISA SSVC
CVSS Vector
The primary mitigation for CVE-2016-20042 is to upgrade to a patched version of Threaded USENET News Reader. As a temporary workaround, restricting user access to the application and carefully scrutinizing command-line arguments could reduce the risk. Consider implementing input validation to limit the size of arguments passed to the application. While a WAF or proxy is unlikely to be effective in this scenario due to the local nature of the vulnerability, monitoring system logs for unusual process activity related to Threaded USENET News Reader is recommended. After upgrading, confirm the fix by attempting to trigger the overflow with a large command-line argument; the application should either reject the argument or handle it gracefully without crashing.
Update TRN to a version later than 3.6-23 or consider using a different USENET newsreader. The vulnerability allows arbitrary code execution, so it is crucial to take steps to mitigate the risk.
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CVE-2016-20042 is a buffer overflow vulnerability in Threaded USENET News Reader version 3.6-23 that allows local attackers to execute arbitrary code.
You are affected if you are running Threaded USENET News Reader version 3.6-23 and have not upgraded to a patched version.
Upgrade to a patched version of Threaded USENET News Reader. Check the vendor's website for available updates.
There is no current evidence of active exploitation, but the vulnerability's nature makes it potentially exploitable.
Consult the vendor's website or security mailing lists for the official advisory related to CVE-2016-20042.
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