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major vulnerability· requires attention

Widely deployed Junos IPsec on SRX/MX; unauthenticated network DoS could disrupt enterprise VPN infrastructure.

Networks

CVE-2026-33778

8.7
High
EPSS 0.34%Patch availableApr 10, 2026

Unauthenticated network DoS in Junos IPsec kmd/iked can crash service and halt VPN SAs.

common questions

Is CVE-2026-33778 being exploited?

Not confirmed. CVE-2026-33778 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 0.34% probability of exploitation in the next 30 days.

How severe is CVE-2026-33778?

CVE-2026-33778 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-2026-33778?

Yes. A fix has been recorded for CVE-2026-33778. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-33778 affect?

CVE-2026-33778 affects Juniper Networks Junos OS SRX Series, Juniper Networks Junos OS MX Series. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-33778?

Upgrade to fixed Junos OS release (e.g., 22.4R3-S9 or newer)

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Juniper Networks Junos OS SRX SeriesJuniper Networks Junos OS MX Series
impact

Attacker can crash kmd/iked via malformed ISAKMP, denying new VPN SAs and VPN connectivity.

action required

Patch when possible

affected versions
Juniper Networks Junos OS
  • affected< 22.4R3-S9
  • affected>= 23.2 and < 23.2R2-S6
  • affected>= 23.4 and < 23.4R2-S7
  • affected>= 24.2 and < 24.2R2-S4
  • affected>= 24.4 and < 24.4R2-S3
  • affected>= 25.2 and < 25.2R1-S2, 25.2R2

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.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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