CVE-2026-33797: An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthe

Routine

HIGH 7.4MITIGATEMITIGATE

CVE-2026-33797 is a high-severity flaw (CVSS 7.4) affecting junos, junos os evolved. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker, sending a specific genuine BGP packet in an already established BGP session to reset only that session causing a Denial of Service (DoS). An attacker repeatedly sending the packet will sustain the Denial of Service (DoS).This issue affects Junos OS: * 25.2 versions before 25.2R2 This issue does not affe

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.4 (High)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-20
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 22:10 UTCUpdated Record last modified

juniper junos MITIGATE

Affected: 25.2 · 25.2 r1 · 25.2 r1-s1 · 25.2 r1-s2

Fixed in: no fixed release known

Safe to downgrade to: a release before 25.2

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.

juniper junos os evolved MITIGATE

Affected: 25.2 · 25.2 r1 · 25.2 r1-s1 · 25.2 r1-s2

Fixed in: no fixed release known

Safe to downgrade to: a release before 25.2

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-2026-33797?

junos: mitigate or apply the listed mitigation; junos os evolved: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-33797 being exploited?

CVE-2026-33797 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-2026-33797 affect?

CVE-2026-33797 affects junos, junos os evolved. Severity is high (CVSS 7.4). An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker, sending a specific genuine BGP packet in an already established BGP session to reset only that sessio

How urgent is CVE-2026-33797?

Priority 27/100. High severity

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

← Back to latest CVEs