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
Published Feb 12, 2021
4.8
MEDIUMCVSS 3.1
EPSS 0.56%
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.
Affected products
- Vendor n/a Product Big-IP Defaultn/a
- Version All versions of 12.1.x and 11.6.xStatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n/a | Big-IP | n/a |
|
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
- ≥ 11.6.1 · ≤ 11.6.5
- ≥ 12.1.0 · ≤ 12.1.5
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
No CVSS v3.0 score for this CVE.
AV:N/AC:M/Au:N/C:P/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
Table of values (12 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.56% (0.00555) | 44.28th | v5 (v2026.06.15) |
| Sep 20, 2026 | 0.56% (0.00555) | 45.15th | v5 (v2026.06.15) |
| Jul 20, 2024 | 0.07% (0.00065) | 29.09th | v3 (v2023.03.01) |
| Jun 14, 2024 | 0.07% (0.00065) | 28.67th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.07% (0.00065) | 26.66th | v3 (v2023.03.01) |
| Mar 6, 2023 | 0.89% (0.00885) | 27.89th | v2 (v2022.01.01) |
| Apr 1, 2022 | 0.89% (0.00885) | 24.24th | v2 (v2022.01.01) |
| Feb 4, 2022 | 6.84% (0.06837) | 79.65th | v2 (v2022.01.01) |
| Feb 3, 2022 | 1.84% (0.01840) | 47.83th | v1 |
| Jan 6, 2022 | 1.84% (0.01840) | 47.32th | v1 |
| Jan 5, 2022 | 0.42% (0.00416) | 26.65th | v5 (v2026.06.15) |
| Apr 14, 2021 | 0.42% (0.00416) | 0.00th | v1 |
No CWE recorded.
References (1)
- https://support.f5.com/csp/article/K09121542 x_refsource_MISCVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://support.f5.com/csp/article/K09121542 | x_refsource_MISCVendor Advisory |
Change history (0)
No recorded changes yet.