CVE-2018-5541 — When F5 BIG-IP ASM 13

When F5 BIG-IP ASM 13.0.0-13.1.0.1, 12.1.0-12.1.3.5, 11.6.0-11.6.3.1, or 11.5.1-11.5.6 is processing HTTP requests, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process.

01What is this vulnerability?

When F5 BIG-IP ASM 13.0.0-13.1.0.1, 12.1.0-12.1.3.5, 11.6.0-11.6.3.1, or 11.5.1-11.5.6 is processing HTTP requests, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process.

02Affected products

Vendor	Product	Versions
F5 Networks, Inc.	BIG	IP (ASM) — 13.0.0-13.1.0.1, 12.1.0-12.1.3.5, 11.6.0-11.6.3.1, 11.5.1-11.5.6

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2018-07-25T14:00:00.000Z
• Last modified: 2024-09-16T17:33:47.886Z

09References

• www.securityfocus.com — http://www.securityfocus.com/bid/104906
• support.f5.com — https://support.f5.com/csp/article/K12403422