CVE-2026-103391
Session Smart Router: An attacker-controlled TCP option causes an out-of-bounds write when using the TCP proxy feature
An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks Session Smart Router allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash via a transit TCP packet with a crafted TCP option length.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Session Smart Router: An attacker-controlled TCP option causes an out-of-bounds write when using the TCP proxy feature
An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks Session Smart Router allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash via a transit TCP packet with a crafted TCP option length.
- Record
CVE-2026-103391- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-787
- Updated
- 2026-11-06
EUVDEUVD-2026-112226
An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks Session Smart Router allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash via a transit TCP packet with a crafted TCP option length.
- Record
EUVD-2026-112226- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-06
GitHub AdvisoriesGHSA-mg4c-h4g5-47fv
An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks...
An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks Session Smart Router allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash via a transit TCP packet with a crafted TCP option length.
- Record
GHSA-mg4c-h4g5-47fv- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-787
- Updated
- 2026-11-02
NVD
An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks Session Smart Router allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash via a transit TCP packet with a crafted TCP option length.
- Record
CVE-2026-103391- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-787
- Updated
- 2026-11-06
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | EUVD | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-103391 is a medium vulnerability (CVSS 5.3) in Juniper Networks Session Smart Router, published October 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 10th percentile. No source names a fixed version.