Red Hat libarchive Zip Writer archive_write_set_format_zip.c archive_write_zip_header integer overflow

Summaryinfo

A vulnerability categorized as critical has been discovered in Red Hat libarchive. Affected is the function archive_write_zip_header of the file archive_write_set_format_zip.c of the component Zip Writer. Such manipulation leads to integer overflow. This vulnerability is referenced as CVE-2026-16517. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Red Hat libarchive (affected version unknown). It has been rated as critical. Affected by this issue is the function archive_write_zip_header of the file archive_write_set_format_zip.c of the component Zip Writer. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A signed integer overflow vulnerability was found in libarchive's ZIP writer. In the archive_write_zip_header function in archive_write_set_format_zip.c, when ZIP encryption is enabled and the entry file size is close to INT64_MAX, the addition of the 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.

The advisory is shared for download at access.redhat.com. This vulnerability is handled as CVE-2026-16517 since 07/22/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 07/22/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-47586). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• File Compression Software

Vendor

• Red Hat

Name

• libarchive

License

• open-source

Website

• Vendor: https://www.redhat.com/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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