Unauthenticated RCE in Juniper Session Smart Router DHCP client can fully compromise network routers and disrupt enterprise routing/infrastructure.
CVE-2026-103408
Unauthenticated RCE in Juniper Session Smart Router DHCP client
Is CVE-2026-103408 being exploited?
Not confirmed. CVE-2026-103408 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.31% probability of exploitation in the next 30 days.
How severe is CVE-2026-103408?
CVE-2026-103408 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-103408?
Not known from our data. No patch reference has been recorded for CVE-2026-103408, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-103408 affect?
CVE-2026-103408 affects Juniper Session Smart Router (DHCP client). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-103408?
Follow Juniper advisory, apply vendor fixes/mitigations, isolate DHCP, block untrusted DHCP traffic
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malicious DHCP reply leads to stack buffer overflow allowing unauthenticated remote code execution; attacker can run arbitrary code, control or disrupt routers and traffic.
Immediate action required
- affected< 7.0.5
- affected>= 7.1.0 and < 7.1.7
- affected>= 7.2.0 and < 7.2.3
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.