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VulnerabilityPublished

CVE-2026-103391: Juniper Networks Session Smart Router · Out-of-bounds Write

Affects Juniper Networks Session Smart RouterSource CVE Database V5

0

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

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Juniper NetworksSession Smart RouterAffected
  • >=7.2.0 <7.2.3
Fixed in
  • 7.2.3
Juniper NetworksSession Smart RouterAffected
  • >=7.1.0 <7.1.7
Fixed in
  • 7.1.7
Juniper NetworksSession Smart RouterAffected
  • <7.0.5
Fixed in
  • 7.0.5

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.

References

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