CVE-2021-31349
Session Smart Router: Authentication Bypass Vulnerability
- Published
- Updated
- Reserved
- Assigned by
- juniper
Description
The usage of an internal HTTP header created an authentication bypass vulnerability (CWE-287), allowing an attacker to view internal files, change settings, manipulate services and execute arbitrary code. This issue affects all Juniper Networks 128 Technology Session Smart Router versions prior to 4.5.11, and all versions of 5.0 up to and including 5.0.1.
Timeline
ID reserved
By juniper
- 6 months later
· 6 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 1.7% · top 22% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Weakness
Affected products
Juniper Networks · 128 Technology Session Smart Router
- affected unspecified – < 4.5.11
- affected 5.0 – ≤ 5.0.1
What to do
Solution: 128 Technology has released software updates that address the vulnerability described in this advisory. Fixed Releases: The following 128T software patches have been released to resolve this specific issue: 4.5.11, 5.1.0, and all subsequent releases. Customers who are running 5.0.0 or 5.0.1 should upgrade to 5.1.6 or later. Instructions for upgrading the 128T Networking Platform can be found at https://docs.128technology.com/docs/intro_upgrading .
Workaround: While no workarounds exist for this vulnerability, risk exposure can be mitigated. HTTP access to the SSR occurs on TCP port 443. It is recommended to install firewall rules to permit access only from trusted IP addresses.
References (1)
- https://kb.juniper.net/JSA11256 (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-31349)Record last updated .