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PatchSiren cyber security CVE debrief

CVE-2016-9844 Unzip Project CVE debrief

CVE-2016-9844 is a buffer overflow in the zi_short function in zipinfo.c in Info-Zip UnZip 6.0. According to the published description, a malformed central directory file header with a large compression method value can cause a crash, creating a denial-of-service condition. NVD maps the issue to CWE-119 and scores it as medium severity with availability impact only.

Vendor
Unzip Project
Product
Unzip
CVSS
MEDIUM 4
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-18
Original CVE updated
2026-05-13
Advisory published
2017-01-18
Advisory updated
2026-05-13

Who should care

Administrators, distro maintainers, and developers who rely on Info-Zip UnZip 6.0 to process untrusted archives should pay attention. File ingestion pipelines, automated unpacking jobs, and any system that inspects user-supplied ZIP files are the most relevant exposure points.

Technical summary

The affected component is zi_short in zipinfo.c. The vulnerability is described as a buffer overflow triggered by an unusually large compression method value in the central directory file header of a ZIP archive. NVD lists the affected CPE as cpe:2.3:a:unzip_project:unzip:6.0:*:*:*:*:*:*:* and assigns CVSS v3.0 AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L, with CWE-119 as the primary weakness.

Defensive priority

Moderate. The issue is primarily a crash/availability problem, but it affects a widely used archive utility and can be triggered by malformed input. Systems that automatically unpack untrusted ZIP files should be prioritized for review.

Recommended defensive actions

  • Inventory systems and applications that ship or bundle Info-Zip UnZip 6.0.
  • Apply the vendor or distribution update that addresses the vulnerability.
  • Avoid processing untrusted archives with UnZip 6.0 where possible.
  • Run archive extraction in a sandboxed or low-privilege environment.
  • Monitor for unexpected crashes in workflows that inspect ZIP central directory metadata.

Evidence notes

The NVD record identifies Info-Zip UnZip 6.0 as affected and lists CWE-119, CVSS v3.0 AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L, and a ZIP central-directory-related overflow in zi_short. The supplied references include oss-security postings dated 2016-12-05, a SecurityFocus entry, and an Ubuntu Launchpad issue, all consistent with public disclosure and downstream tracking.

Sources and references

Verified primary and authoritative sources

  • CVE-2016-9844 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2016-9844

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2016-9844 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2016-9844

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.