CVE-2026-33778 PUBLISHED

Junos OS: SRX Series, MX Series: When a specifically malformed first ISAKMP packet is received kmd/iked crashes

Assigner: juniper
Reserved: 23.03.2026 Published: 09.04.2026 Updated: 10.04.2026

An Improper Validation of Syntactic Correctness of Input vulnerability in the IPsec library used by kmd and iked of Juniper Networks Junos OS on SRX Series and MX Series allows an unauthenticated, network-based attacker to cause a complete Denial-of-Service (DoS).

If an affected device receives a specifically malformed first ISAKMP packet from the initiator, the kmd/iked process will crash and restart, which momentarily prevents new security associations (SAs) for from being established. Repeated exploitation of this vulnerability causes a complete inability to establish new VPN connections.

This issue affects Junos OS on

SRX Series and MX Series:

  • all versions before 22.4R3-S9,
  • 23.2 version before 23.2R2-S6,
  • 23.4 version before 23.4R2-S7,
  • 24.2 versions before 24.2R2-S4,
  • 24.4 versions before 24.4R2-S3,
  • 25.2 versions before 25.2R1-S2, 25.2R2.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M
CVSS Score: 8.7

Product Status

Vendor Juniper Networks
Product Junos OS
Versions Default: unaffected
  • affected from 0 to 22.4R3-S9 (excl.)
  • affected from 23.2 to 23.2R2-S6 (excl.)
  • affected from 23.4 to 23.4R2-S7 (excl.)
  • affected from 24.2 to 24.2R2-S4 (excl.)
  • affected from 24.4 to 24.4R2-S3 (excl.)
  • affected from 25.2 to 25.2R1-S2, 25.2R2 (excl.)

Affected Configurations

An SRX or MX device is only exploitable when it is configured for IPsec VPN services.

Exploits

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

Workarounds

There are no known workarounds for this issue.

Solutions

The following software releases have been updated to resolve this specific issue: 22.4R3-S9, 23.2R2-S6, 23.4R2-S7, 24.2R2-S4, 24.4R2-S3, 25.2R1-S2, 25.2R2, 25.4R1, and all subsequent releases.

References

Problem Types

  • CWE-1286 Improper Validation of Syntactic Correctness of Input CWE