Bug 2505492 (CVE-2026-16517)

Summary:	CVE-2026-16517 libarchive: libarchive: Signed Integer Overflow in archive_write_zip_header
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	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.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-21 22:33:49 UTC

A signed integer overflow flaw was found in libarchive's ZIP writer. The issue occurs in the archive_write_zip_header function in archive_write_set_format_zip.c when writing a ZIP entry with a known file size while ZIP encryption (e.g., AES-256) is enabled. When the entry size is close to INT64_MAX, adding the encryption overhead (additional_size) to zip->entry_uncompressed_size triggers a signed integer overflow, leading to undefined behavior per the C standard. This could result in incorrect Zip64 extension decisions or potential memory corruption.

The vulnerability is in the write path only and requires both ZIP encryption to be enabled and a file size near INT64_MAX, making real-world exploitation unlikely.

Upstream issue: https://github.com/libarchive/libarchive/issues/3225
Upstream fix: https://github.com/libarchive/libarchive/pull/3228

Comment 1 Jon Orris 2026-09-21 22:51:25 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:69553 https://access.redhat.com/errata/RHSA-2026:69553