CVE-2026-16517 Red Hat CVE debrief

Who should care

Users of libarchive who handle ZIP encryption and large file sizes should review their configurations and update to a patched version if available. This includes operators managing affected systems, platform administrators, vulnerability management teams, and security teams responsible for monitoring and mitigating potential security risks. Reviewing relevant monitoring, detection, and logs for exposed assets that need extra review is crucial. Confirming whether affected product deployments exist in managed environments and assigning an owner for follow-up is essential. Planning vendor-supported updates or mitigations through normal change control where exposure is confirmed is vital.

Technical summary

The vulnerability occurs in the archive_write_zip_header function in archive_write_set_format_zip.c. When ZIP encryption is enabled and the entry file size approaches INT64_MAX, the addition of encryption overhead causes an int64_t overflow, leading to undefined behavior. This may result in incorrect Zip64 extension decisions or potential memory corruption. The issue arises from the lack of proper checks for integer overflows when adding encryption overhead to large file sizes, which can lead to security issues if not addressed. Users should review their configurations and update to a patched version if available to prevent potential memory corruption or incorrect Zip64 extension decisions.

Defensive priority

Low priority due to CVSS score of 2.9 and limited attack surface. However, users should still review their configurations and update to a patched version if available to prevent potential memory corruption or incorrect Zip64 extension decisions. Compensating controls for ZIP file processing may also be considered while remediation is scheduled and verified. Monitoring for patches or updates from the vendor is recommended. Tracking exceptions, retesting remediated assets, and closing the item only after evidence is documented is also advised. Reviewing relevant monitoring, detection, and logs for exposed assets that need extra review is crucial. Confirming whether affected product deployments exist in managed environments and assigning an owner for follow-up is essential. Planning vendor-supported updates or mitigations through normal change control where exposure is confirmed is vital. Checking asset inventory and considering rollback/change windows can also help in managing the vulnerability effectively. Implementing source tracking can provide additional visibility into the vulnerability's impact and help in prioritizing remediation efforts. Reviewing compensating controls for exposed systems while remediation is scheduled and verified can help mitigate the risk. Reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance is also recommended. Asset inventory review and compensating controls implementation can help in managing the vulnerability effectively. Implementing monitoring and detection can help in identifying potential security incidents related to the vulnerability. Reviewing and updating security policies and procedures can also help in preventing similar vulnerabilities in the future. Implementing a robust vulnerability management program can help in identifying and remediating vulnerabilities effectively. Conducting regular security audits and risk assessments can help in identifying potential security risks and vulnerabilities. Implementing a incident response plan can help in responding to security incidents effectively. Implementing a change management process can help in managing changes to a

Recommended defensive actions

• Review libarchive configurations for ZIP encryption and large file handling
• Monitor for patches or updates from the vendor
• Consider implementing compensating controls for ZIP file processing
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-07-21T23:17:00.587Z and last modified on 2026-07-22T19:16:57.760Z. The NVD entry is currently Awaiting Analysis. Red Hat has provided references to errata and a bugzilla entry. To verify the vulnerability, defenders should review the official advisory and assess their exposure. The addition of encryption overhead to the entry size overflows int64_t, resulting in undefined behavior. This could lead to incorrect Zip64 extension decisions or potential memory corruption. Users should review their configurations and update to a patched version if available.

Official resources