CVE-2026-103391: Juniper Networks Session Smart Router · Out-of-bounds Write
Affects Juniper Networks Session Smart RouterSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium · fixed in 7.2.3 : update Juniper Networks Session Smart Router when convenient.
Data as of 28 Oct 2026, 17:22 UTC
- Patch
- Available – fixed in 7.2.3, 7.1.7, 7.0.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Juniper Networks Session Smart Router to 7.2.3, 7.1.7 or 7.0.5.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Juniper NetworksSession Smart Router | Affected
| Fixed in
|
| Juniper NetworksSession Smart Router | Affected
| Fixed in
|
| Juniper NetworksSession Smart Router | Affected
| Fixed in
|
AI-suggested
Fixed versions 7.0.5, 7.1.7, and 7.2.3 are available and should be applied to remediate this vulnerability. No other mitigation steps are indicated. Users should upgrade affected devices to one of these fixed releases to resolve the issue.
Description
CVE-2026-103391 is an out-of-bounds write vulnerability in the TCP proxy/optimization path of Juniper Networks Session Smart Router. It allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash by sending a transit TCP packet with a specially crafted TCP option length. The vulnerability affects multiple versions prior to fixed releases 7.0.5, 7.1.7, and 7.2.3. The CVSS score is 5.3, indicating a medium severity level.