Quick answers
- Is CVE-2026-103392 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-103392 being exploited in the wild.
- How severe is CVE-2026-103392?
- Medium severity, with a CVSS score of 4.8, published 28 October 2026.
- Which products and versions are affected?
- Juniper Networks Session Smart Router.
- Is there a fix for CVE-2026-103392?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-103392 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-103392?
- Check whether you run Juniper Networks Session Smart Router. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
An out-of-bounds write vulnerability exists in TCP header processing when handling SACK (Selective Acknowledgment) options with oversized length fields. An unauthenticated attacker on the network can send a malicious transit TCP packet to trigger the flaw, corrupting TCP payload data and causing session desynchronization. No authentication or user interaction is required.
Affected products
- Juniper Networks Session Smart Router
Timeline
- 2026-10-28: disclosed