CVE-2026-33800

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM 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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.5Exploit: None knownExposed services: Not assessed

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

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, and LC2101/2103 and LC480. 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
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.3%
EPSS %ILE
17th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 9, 2026

Last Modified

August 26, 2026

Advisory Details (1)

Auto-updated Jul 9, 2026
No fix on record 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 / 40× 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.

Showing the most recent 100 of 177 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:12 UTCEPSS rescore
  3. 2026-10-07 23:47 UTCEPSS rescore
  4. 2026-10-06 15:17 UTCEPSS rescore
  5. 2026-10-05 17:42 UTCEPSS rescore
  6. 2026-10-04 23:22 UTCEPSS rescore
  7. 2026-10-03 14:25 UTCEPSS rescore
  8. 2026-10-01 19:49 UTCEPSS rescore
  9. 2026-10-01 16:01 UTCEG score recompute
  10. 2026-10-01 16:01 UTCGHSA enrichment
  11. 2026-09-30 15:03 UTCEPSS rescore
  12. 2026-09-28 13:51 UTCEPSS rescore
  13. 2026-09-28 10:26 UTCEG score recompute
  14. 2026-09-28 10:26 UTCGHSA enrichment
  15. 2026-09-27 13:48 UTCEPSS rescore
  16. 2026-09-26 15:58 UTCEPSS rescore
  17. 2026-09-26 00:26 UTCEPSS rescore
  18. 2026-09-24 11:23 UTCEG score recompute
  19. 2026-09-24 11:23 UTCGHSA enrichment
  20. 2026-09-23 05:53 UTCEG score recompute
  21. 2026-09-23 05:53 UTCGHSA enrichment
  22. 2026-09-20 20:15 UTCEPSS rescore
  23. 2026-09-18 19:28 UTCEPSS rescore
  24. 2026-09-18 19:28 UTCEPSS rescore
  25. 2026-09-18 05:34 UTCEG score recompute
Show 75 more
  1. 2026-09-18 05:34 UTCGHSA enrichment
  2. 2026-09-17 19:30 UTCEPSS rescore
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-15 03:11 UTCEPSS rescore
  6. 2026-09-14 08:13 UTCEG score recompute
  7. 2026-09-14 08:13 UTCGHSA enrichment
  8. 2026-09-13 16:47 UTCEPSS rescore
  9. 2026-09-13 08:17 UTCEG score recompute
  10. 2026-09-13 08:17 UTCGHSA enrichment
  11. 2026-09-12 15:01 UTCEPSS rescore
  12. 2026-09-12 03:21 UTCEG score recompute
  13. 2026-09-12 03:21 UTCGHSA enrichment
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-11 09:37 UTCEPSS rescore
  16. 2026-09-10 09:34 UTCEPSS rescore
  17. 2026-09-08 22:00 UTCEPSS rescore
  18. 2026-09-07 16:01 UTCEPSS rescore
  19. 2026-09-06 13:47 UTCEPSS rescore
  20. 2026-09-05 22:11 UTCEG score recompute
  21. 2026-09-05 22:11 UTCGHSA enrichment
  22. 2026-09-04 05:06 UTCEPSS rescore
  23. 2026-09-02 14:12 UTCEPSS rescore
  24. 2026-09-01 13:53 UTCEPSS rescore
  25. 2026-09-01 04:39 UTCEPSS rescore
  26. 2026-09-01 04:39 UTCEPSS rescore
  27. 2026-08-30 19:17 UTCEPSS rescore
  28. 2026-08-30 06:43 UTCEG score recompute
  29. 2026-08-30 06:43 UTCGHSA enrichment
  30. 2026-08-30 01:22 UTCEPSS rescore
  31. 2026-08-28 21:41 UTCEPSS rescore
  32. 2026-08-27 21:44 UTCEG score recompute
  33. 2026-08-27 21:44 UTCGHSA enrichment
  34. 2026-08-27 14:25 UTCEPSS rescore
  35. 2026-08-26 17:44 UTCEG score recompute
  36. 2026-08-26 17:44 UTCGHSA enrichment
  37. 2026-08-26 14:46 UTCEPSS rescore
  38. 2026-08-26 03:48 UTCEG score recompute
  39. 2026-08-26 03:48 UTCGHSA enrichment
  40. 2026-08-25 13:49 UTCEPSS rescore
  41. 2026-08-25 01:20 UTCEG score recompute
  42. 2026-08-25 01:20 UTCGHSA enrichment
  43. 2026-08-24 14:17 UTCEPSS rescore
  44. 2026-08-24 01:25 UTCGHSA enrichment
  45. 2026-08-23 01:29 UTCEG score recompute
  46. 2026-08-23 01:29 UTCGHSA enrichment
  47. 2026-08-23 00:19 UTCEPSS rescore
  48. 2026-08-22 01:29 UTCEG score recompute
  49. 2026-08-22 01:29 UTCGHSA enrichment
  50. 2026-08-21 23:49 UTCEPSS rescore
  51. 2026-08-21 01:35 UTCEG score recompute
  52. 2026-08-21 01:35 UTCGHSA enrichment
  53. 2026-08-20 22:55 UTCEPSS rescore
  54. 2026-08-20 22:55 UTCEPSS rescore
  55. 2026-08-20 01:39 UTCEG score recompute
  56. 2026-08-20 01:39 UTCGHSA enrichment
  57. 2026-08-19 17:03 UTCEPSS rescore
  58. 2026-08-18 20:41 UTCEG score recompute
  59. 2026-08-18 20:41 UTCGHSA enrichment
  60. 2026-08-18 13:48 UTCEPSS rescore
  61. 2026-08-17 14:42 UTCEG score recompute
  62. 2026-08-17 14:42 UTCGHSA enrichment
  63. 2026-08-17 13:47 UTCEPSS rescore
  64. 2026-08-16 14:56 UTCEPSS rescore
  65. 2026-08-16 14:48 UTCGHSA enrichment
  66. 2026-08-15 14:54 UTCEG score recompute
  67. 2026-08-15 14:54 UTCGHSA enrichment
  68. 2026-08-15 01:30 UTCEPSS rescore
  69. 2026-08-14 14:59 UTCEG score recompute
  70. 2026-08-14 14:59 UTCGHSA enrichment
  71. 2026-08-13 22:00 UTCEPSS rescore
  72. 2026-08-13 15:04 UTCGHSA enrichment
  73. 2026-08-12 15:09 UTCEG score recompute
  74. 2026-08-12 15:09 UTCGHSA enrichment
  75. 2026-08-12 13:50 UTCEPSS rescore

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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 on July 9, 2026, with the most recent update on August 26, 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 0.3% probability of exploitation in the next 30 days (17th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33800?
CVE-2026-33800 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-33800?
No fix for CVE-2026-33800 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-33800 are linked in the Vendor Advisories panel on this page.

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