CVE-2026-33800

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-09. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

An Unchecked Input for Loop Condition vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS).Micro-BFD session flaps generate respective up/down events which are queued by PFEMAN for processing. Especially in a Virtual-Chassis (VC) scenario with locality‑bias configured, processing takes a significant amount of time for each event. If these sessions keep flapping, new events are constantly added, and in turn PFEMAN never completes processing these events. This results in the PFEMAN watchdog timer expiring, which causes the FPC to crash and restart, representing a complete service outage.

This issue only affects MX series FPCs up to and including MPC9. It does not affect MPC10/11, LC4800/9600 and MX304.

This issue affects Junos OS on MX Series:

* all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S8, * 24.2 versions before 24.2R2-S4, * 24.4 versions before 24.4R2-S3, * 25.2 versions before 25.2R2.

CVSS v3
6.5
EG Score
6.5(high)
EPSS
18.5%
KEV
Not listed

Published

July 9, 2026

Last Modified

July 10, 2026

Advisory Details (1)

Auto-updated Jul 9, 2026
No patch confirmed yet.
generic

CEC Juniper Community

https://supportportal.juniper.net/JSA110075

Vendor Advisories for CVE-2026-33800(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 7× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 20:54 UTCEG score recompute
  2. 2026-07-11 20:54 UTCGHSA enrichment
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-10 21:00 UTCEG score recompute
  5. 2026-07-10 21:00 UTCGHSA enrichment
  6. 2026-07-09 21:05 UTCEG score recompute
  7. 2026-07-09 21:05 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-33800?
CVE-2026-33800 is a medium vulnerability published on July 9, 2026. An Unchecked Input for Loop Condition vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS).Micro-BFD session flaps generate respective up/down events which are queued by PFEMAN…
When was CVE-2026-33800 disclosed?
CVE-2026-33800 was first published in the National Vulnerability Database on July 9, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33800 actively exploited?
CVE-2026-33800 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 18.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-33800?
CVE-2026-33800 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-33800?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33800, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-33800

Explore →

Is Your Infrastructure Affected by CVE-2026-33800?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs