# CVE-2026-114104: adm-zip inconsistent entry resolution in ZIP extraction

Source: https://junglewise.ai/threats/cve-2026-114104-adm-zip-before-0-6-1-contains-an-inconsistent-entry-resolution  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-114104 · Severity: medium · CVSS 5.9 · Published 2026-10-21

adm-zip is a JavaScript library for reading and writing ZIP archives. The library has a flaw where duplicate entry names in a ZIP file are handled inconsistently: one function returns the last duplicate while another writes the first, allowing attackers to bypass content validation. An application that validates a ZIP entry before extraction could approve one file's content while actually writing different bytes to disk.

## Quick answers

**Is CVE-2026-114104 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-114104 being exploited in the wild.

**How severe is CVE-2026-114104?** Medium severity, with a CVSS score of 5.9, published 21 October 2026.

**Which products and versions are affected?** Adm-Zip before 0.6.1.

**Is there a fix for CVE-2026-114104?** Yes: fixed in 0.6.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-114104 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-114104?** Check whether you run Adm-Zip at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 0.6.1

## Technical details

The vulnerability stems from inconsistent data structure usage: getEntry() lookups use an entry table that retains only the last duplicate entry, while extractAllTo() iterates an entry list that contains all duplicates in order. An attacker crafts a malicious ZIP with duplicate entry names to cause getEntry() and extractAllTo() to resolve the same name to different content, bypassing validate-then-extract patterns.

## Affected products

- adm-zip before 0.6.1

## Timeline

- 2026-09-11: disclosed
- 2026-10-21: advisory

## References

- [https://github.com/cthackers/adm-zip/security/advisories/GHSA-p634-w6r4-rjp2](https://github.com/cthackers/adm-zip/security/advisories/GHSA-p634-w6r4-rjp2)
- [https://www.vulncheck.com/advisories/adm-zip-before-0.6.1-duplicate-zip-entry-name-validation-bypass](https://www.vulncheck.com/advisories/adm-zip-before-0.6.1-duplicate-zip-entry-name-validation-bypass)

## Related threats

- [adm-zip duplicate ZIP entry name validation bypass](https://junglewise.ai/threats/adm-zip-duplicate-zip-entry-names-getentry-and-extractallto-resolve-to-42f08f8e)