CVE-2021-22981
On all versions of BIG-IP 12.1.x and 11.6.x, the original TLS protocol includes a weakness in the master secret negotiation that is mitigated by the Extended Master Secret (EMS) extension defined in RFC 7627.
Does this matter?
Lower severity and a low EPSS score (0.56%). Track it; it rarely justifies an emergency change on its own.
Description
On all versions of BIG-IP 12.1.x and 11.6.x, the original TLS protocol includes a weakness in the master secret negotiation that is mitigated by the Extended Master Secret (EMS) extension defined in RFC 7627. TLS connections that do not use EMS are vulnerable to man-in-the-middle attacks during renegotiation. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.
- CVSS 3.1
- 4.8 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS
- 0.56% probability · 46th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- f5/big-ip access policy manager · f5/big-ip advanced firewall manager · f5/big-ip advanced web application firewall · f5/big-ip analytics · f5/big-ip application acceleration manager · f5/big-ip application security manager · f5/big-ip ddos hybrid defender · f5/big-ip domain name system · f5/big-ip fraud protection service · f5/big-ip global traffic manager · f5/big-ip link controller · f5/big-ip local traffic manager · f5/big-ip policy enforcement manager · f5/big-ip ssl orchestrator
- Source
- f5sirt@f5.com
EPSS 0.6% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://support.f5.com/csp/article/K09121542Vendor Advisory
- https://support.f5.com/csp/article/K09121542Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.