CVE-2026-33774: An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of

Q: How do I fix CVE-2026-33774?

junos: upgrade to 23.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-33774 being exploited?

CVE-2026-33774 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-33774 affect?

CVE-2026-33774 affects junos. Severity is medium (CVSS 6.5). An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the configured firewall filter

Q: How urgent is CVE-2026-33774?

Priority 29/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 6.5REMOTEUPGRADE

CVE-2026-33774 is a medium-severity flaw (CVSS 6.5) affecting junos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the configured firewall filter and access the control-plane of the device. On MX platforms with MPC10, MPC11, LC4800 or LC9600 line cards, and MX304, firewall filters applied on a loopback interface lo0.n (where n is a non-0 number) don

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-754
Published	2026-04-09
Last modified	2026-10-26

Publisher (CNA): Juniper Networks, Inc. · Vendor: juniper

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-09 22:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

juniper junos UPGRADE

Affected: < 23.2 · 23.2 r1 · 23.2 r1-s1 · 23.2 r1-s2 · 23.2 r2 · 23.2 r2-s1 · 23.2 r2-s2 · 23.2 r2-s3

Fixed in: 23.2

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33774?

junos: upgrade to 23.2. Exact commands for each OS are on this page.

Is CVE-2026-33774 being exploited?

CVE-2026-33774 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33774 affect?

CVE-2026-33774 affects junos. Severity is medium (CVSS 6.5). An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the configured firewall filter

How urgent is CVE-2026-33774?

Priority 29/100. Remotely exploitable, no login, no user action

Software pages

Juniper Junos vulnerabilities

Related CVEs

CVE-2026-33790 HIGH 7.5 UPGRADE An Improper Check for Unusual or Exceptional Conditions vulnerability in the flow daemon (flowd) of Juniper Ne
CVE-2026-33791 MEDIUM 6.7 UPGRADE UPGRADE An OS Command Injection vulnerability in the CLI processing of Juniper Networks Junos OS and Junos OS Evolved
CVE-2026-33785 HIGH 8.8 MITIGATE A Missing Authorization vulnerability in the CLI of Juniper Networks Junos OS on MX Series allows a local, aut
CVE-2026-33793 HIGH 7.8 UPGRADE UPGRADE An Execution with Unnecessary Privileges vulnerability in the User Interface (UI) of Juniper Networks Junos OS
CVE-2026-33773 MEDIUM 5.8 MITIGATE An Incorrect Initialization of Resource vulnerability in the packet forwarding engine (pfe) of Juniper Network

References

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