Juniper Junos networking flaw can disrupt OVSDB control plane and enable RCE on widely deployed enterprise network infrastructure.
CVE-2026-103994
Heap overflow in Juniper Junos VXLAN daemon enables OVSDB outage or RCE via malicious SDN-controller
Is CVE-2026-103994 being exploited?
Not confirmed. CVE-2026-103994 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 0.43% probability of exploitation in the next 30 days.
How severe is CVE-2026-103994?
CVE-2026-103994 is rated High with a CVSS score of 8.7. 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-2026-103994?
Not known from our data. No patch reference has been recorded for CVE-2026-103994, 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-2026-103994 affect?
CVE-2026-103994 affects Juniper Junos OS - VXLAN Gateway Daemon (vgd), Devices running OVS/OVSDB with Junos VXLAN, SDN controllers interfacing with vgd. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-103994?
Isolate devices, block untrusted SDN controllers, follow Juniper advisory and apply vendor patch when available.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
A malicious or compromised SDN-controller can trigger a heap overflow to crash OVSDB control plane and potentially achieve remote code execution.
Immediate action required
- affected< 23.2R2-S7.7
- affected>= 23.4 and < 23.4R2-S8.13
- affected>= 24.2 and < 24.2R2-S5.5
- affected>= 24.4 and < 24.4R2-S5
- affected>= 25.2 and < 25.2R2-S2
- affected>= 25.4 and < 25.4R1-S3
- affected>= 26.2 and < 26.2R1-S2
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.