SB2025070765 - Fedora 43 update for zsync 



SB2025070765 - Fedora 43 update for zsync

Published: July 7, 2025

Security Bulletin ID SB2025070765
Severity
Medium
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 50% Low 50%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 secuirty vulnerabilities.


1) Denial of service (CVE-ID: CVE-2016-9840)

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists in zlib due to out-of-bounds pointer arithmetic in inftrees.c. A remote attacker can send a specially crafted document, trick the victim into opening it, and cause the application to crash.

Successful exploitation of the vulnerability results in denial of service.

2) Incorrect calculation (CVE-ID: CVE-2025-4638)

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to usage of a vulnerable version of the inftrees.c component from the zlib library. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.


Remediation

Install update from vendor's website.