CVE-2026-16517

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Integer Overflow in libarchive ZIP Writer

Publication date: 2026-07-21

Last updated on: 2026-07-22

Assigner: Red Hat, Inc.

Description

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-21

Last Modified

2026-07-22

Generated

2026-08-11

AI Q&A

2026-07-22

EPSS Evaluated

2026-08-09

NVD

CVE-2026-16517

EUVD

EUVD-2026-47586

Affected Vendors & Products

Vendor	Product	Version / Range
libarchive	libarchive	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
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 occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

Executive Summary

This is a signed integer overflow vulnerability in libarchive's ZIP writer. When ZIP encryption is enabled and a file size is near INT64_MAX, adding encryption overhead causes an overflow in int64_t. This leads to undefined behavior, potentially causing incorrect Zip64 extension decisions or memory corruption.

Detection Guidance

To detect this vulnerability, check if your system uses a vulnerable version of libarchive with ZIP encryption enabled. Inspect the libarchive version and search for ZIP operations in logs or processes. No specific commands are provided in the context.

Impact Analysis

The impact is limited due to specific conditions required for exploitation. It could cause crashes or data corruption when creating encrypted ZIP files with very large entries. However, real-world exploitation is unlikely as it requires both encryption enabled and file sizes near INT64_MAX.

Compliance Impact

This vulnerability does not directly impact compliance with GDPR or HIPAA as it involves a low-severity signed integer overflow in libarchive's ZIP writer with unlikely real-world exploitation. Compliance risks would only arise if the vulnerability were exploited to corrupt data during ZIP encryption operations, which is not indicated in the provided context.

Mitigation Strategies

Update libarchive to the latest patched version. Disable ZIP encryption if not required. Monitor for unusual ZIP operations or memory corruption issues. Apply vendor patches promptly.

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