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TI-2026-26152 Aliases CVE-2026-33774GHSA-3p5v-chx4-4483

Junos OS: MX Series: Firewall filters on lo0.<non-0> in the default routing instance are not in effect

Priority LOW 30CWE-754Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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't get executed when lo0.n is in the global VRF / default routing-instance. An affected configuration would be: user@host# show configuration interfaces lo0 | display set set interfaces lo0 unit 1 family inet filter input <filter-name> where a firewall filter is applied to a non-0 loopback interface, but that loopback interface is not referred to in any routing-instance (RI) configuration, which implies that it's used in the default RI. The issue can be observed with the CLI command: user@device> show firewall counter filter <filter_name> not showing any matches. This issue affects Junos OS on MX Series: * all versions before 23.2R2-S6, * 23.4 versions before 23.4R2-S7, * 24.2 versions before 24.2R2, * 24.4 versions before 24.4R2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0018 7th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 23.2R2-S6, 23.4R2-S7, 24.2R2 +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
JuniperJunos OSbefore 23.2R2-S6; 23.4 to before 23.4R2-S7; 24.2 to before 24.2R2; 24.4 to before 24.4R223.2R2-S6, 23.4R2-S7, 24.2R2, 24.4R2Patch availableCNA
  • Junos OS VendorJuniper Affected before 23.2R2-S6; 23.4 to before 23.4R2-S7; 24.2 to before 24.2R2; 24.4 to before 24.4R2 Fixed in 23.2R2-S6, 23.4R2-S7, 24.2R2, 24.4R2 Patch available CNA

CPE configurations NVD · 30

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*before 23.2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:*23.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:*23.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:*23.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:*23.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:*23.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:*23.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:*23.2 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s4:*:*:*:*:*:*23.2 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.2:r2-s5:*:*:*:*:*:*23.2 r2-s5VulnerableJuniper
  • cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* Versions before 23.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* Versions 23.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* Versions 23.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* Versions 23.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:* Versions 23.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:* Versions 23.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:* Versions 23.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:* Versions 23.2 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s4:*:*:*:*:*:* Versions 23.2 r2-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.2:r2-s5:*:*:*:*:*:* Versions 23.2 r2-s5 Vulnerable ·Juniper
Show 20 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:*23.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:*23.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:*23.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:*23.4 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s4:*:*:*:*:*:*23.4 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s5:*:*:*:*:*:*23.4 r2-s5VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s6:*:*:*:*:*:*23.4 r2-s6VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:*24.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:*24.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:*24.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:*24.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:*24.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:*24.4 r1-s3VulnerableJuniper
cpe:2.3:h:juniper:lc4800:-:*:*:*:*:*:*:*not specified by NVDRunning onJuniper
cpe:2.3:h:juniper:mpc10:-:*:*:*:*:*:*:*not specified by NVDRunning onJuniper
cpe:2.3:h:juniper:mpc11:-:*:*:*:*:*:*:*not specified by NVDRunning onJuniper
cpe:2.3:h:juniper:mx304:-:*:*:*:*:*:*:*not specified by NVDRunning onJuniper
  • cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:* Versions 23.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:* Versions 23.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:* Versions 23.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:* Versions 23.4 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s4:*:*:*:*:*:* Versions 23.4 r2-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s5:*:*:*:*:*:* Versions 23.4 r2-s5 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s6:*:*:*:*:*:* Versions 23.4 r2-s6 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:* Versions 24.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:* Versions 24.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:* Versions 24.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* Versions 24.4 r1-s3 Vulnerable ·Juniper
  • cpe:2.3:h:juniper:lc4800:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
  • cpe:2.3:h:juniper:mpc10:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
  • cpe:2.3:h:juniper:mpc11:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
  • cpe:2.3:h:juniper:mx304:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper

Remediation

  • Fix · CNA Junos OS (Juniper Networks) Fixed in 23.2R2-S6, 23.4R2-S7, 24.2R2, 24.4R2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33774
  2. 2026-10-03 Alias added: GHSA-3p5v-chx4-4483

References

Advisory 1

  • TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
  • TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
  • TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
  • TI-2023-18644 Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files KEVCVSS 3.1MEDIUM 5.3
  • TI-2023-18640 Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files KEVCVSS 3.1MEDIUM 5.3
See all 792 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences