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Fencer Vulns
medium 6.5

CVE-2023-36850 json

Junos OS: MX Series: An MPC will crash upon receipt of a malformed CFM packet.

published 2023-07-14 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-40770

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

An Improper Validation of Specified Index, Position, or Offset in Input vulnerability in the Connectivity Fault Management(CFM) module of Juniper Networks Junos OS on MX Series(except MPC10, MPC11 and LC9600) allows an adjacent attacker on the local broadcast domain to cause a Denial of Service(DoS).

Upon receiving a malformed CFM packet, the MPC crashes. Continued receipt of these packets causes a sustained denial of service. This issue can only be triggered when CFM hasn't been configured.

This issue affects: Juniper Networks Junos OS All versions prior to 19.1R3-S10 on MX Series; 19.2 versions prior to 19.2R3-S7 on MX Series; 19.3 versions prior to 19.3R3-S8 on MX Series; 19.4 versions prior to 19.4R3-S12 on MX Series; 20.1 version 20.1R1 and later versions on MX Series; 20.2 versions prior to 20.2R3-S7 on MX Series; 20.3 version 20.3R1 and later versions on MX Series; 20.4 versions prior to 20.4R3-S7 on MX Series; 21.1 versions prior to 21.1R3-S5 on MX Series; 21.2 versions prior to 21.2R3-S4 on MX Series; 21.3 versions prior to 21.3R3-S4 on MX Series; 21.4 versions prior to 21.4R3-S3 on MX Series; 22.1 versions prior to 22.1R3-S2 on MX Series; 22.2 versions prior to 22.2R3 on MX Series; 22.3 versions prior to 22.3R2, 22.3R3 on MX Series; 22.4 versions prior to 22.4R2 on MX Series.

Patch / fix

  • Juniper Networks Junos OS 19.1R3-S10, 19.2R3-S7, 19.3R3-S8, 19.4R3-S12, 20.2R3-S7, 20.4R3-S7, 21.1R3-S5, 21.2R3-S4, 21.3R3-S4, 21.4R3-S3, 22.1R3-S2, 22.2R3, 22.3R2, 22.4R2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Juniper Networks Junos OS

Classification

Weakness
  • CWE-1285 Improper Validation of Specified Index, Position, or Offset in Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.