CVE-2026-33790: Junos OS: SRX Series: In a NAT64 configuration, receipt of a specific, malformed ICMPv6 packet will cause the srxpfe process to crash and restart.

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-09 · updated 2026-10-26
Weakness: CWE-754

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the flow daemon (flowd) of Juniper Networks Junos OS on SRX Series allows an attacker sending a specific, malformed ICMPv6 packet to cause the srxpfe process to crash and restart. Continued receipt and processing of these packets will repeatedly crash the srxpfe process and sustain the Denial of Service (DoS) condition. During NAT64 translation, receipt of a specific, malformed ICMPv6 packet destined to the device will cause the srxpfe process to crash and restart. This issue cannot be triggered using IPv4 nor other IPv6 traffic. This issue affects Junos OS on SRX Series: * all versions before 21.2R3-S10, * all versions of 21.3, * from 21.4 before 21.4R3-S12, * all versions of 22.1, * from 22.2 before 22.2R3-S8, * all versions of 22.4, * from 22.4 before 22.4R3-S9, * from 23.2 before 23.2R2-S6, * from 23.4 before 23.4R2-S7, * from 24.2 before 24.2R2-S3, * from 24.4 before 24.4R2-S3, * from 25.2 before 25.2R1-S2, 25.2R2.

Affected products

Juniper Junos OS: before 21.2; 21.2, 21.2-r1, 21.2-r1-s1, 21.2-r1-s2, 21.2-r2, 21.2-r2-s1 (+102) — fixed in 21.2

How to fix

Upgrade to a fixed version: Juniper Junos OS 21.2. Check the vendor advisory for mitigations.

References

https://kb.juniper.net/JSA107874

Get alerted when CVE-2026-33790 or the next vulnerability affects your stack