Vulnerability-Lookup

GHSA-3P5V-CHX4-4483

Vulnerability from github – Published: 2026-04-10 00:30 – Updated: 2026-04-10 00:30

Details

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

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

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.

Severity

6.5 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

6.9 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/AU:Y/R:U/RE:L

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{
  "affected": [],
  "aliases": [
    "CVE-2026-33774"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-754"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-09T22:16:25Z",
    "severity": "MODERATE"
  },
  "details": "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.\n\nOn MX platforms with \n\nMPC10, MPC11, LC4800 or LC9600\n\nline cards, and MX304, firewall filters applied on a loopback interface lo0.n (where n is a non-0 number) don\u0027t get executed when lo0.n is in the global VRF / default routing-instance.\n\n An affected configuration would be:\n\nuser@host# show configuration interfaces lo0 | display set\nset interfaces lo0 unit 1 family inet filter input \u003cfilter-name\u003e\n\nwhere 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\u0027s used in the default RI.\n\nThe issue can be observed with the CLI command:\n\nuser@device\u003e show firewall counter filter \u003cfilter_name\u003e \n\nnot showing any matches.\n\nThis issue affects Junos OS on MX Series:\n\n  *  all versions before 23.2R2-S6,\n  *  23.4 versions before 23.4R2-S7,\n  *  24.2 versions before 24.2R2,\n  *  24.4 versions before 24.4R2.",
  "id": "GHSA-3p5v-chx4-4483",
  "modified": "2026-04-10T00:30:29Z",
  "published": "2026-04-10T00:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33774"
    },
    {
      "type": "WEB",
      "url": "https://kb.juniper.net/JSA107865"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:L/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-33774 (GCVE-0-2026-33774)

Vulnerability from cvelistv5 – Published: 2026-04-09 21:34 – Updated: 2026-04-10 14:14

Title

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

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.

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

6.9 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/AU:Y/R:U/RE:L

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-10 14:14 UTC

CWE

CWE-754 - Improper Check for Unusual or Exceptional Conditions

Assigner

juniper mitre root Scorecard

References

1 reference

URL	Tags
https://kb.juniper.net/JSA107865	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Juniper Networks	Junos OS	Affected: 0 , < 23.2R2-S6 (semver) Affected: 23.4 , < 23.4R2-S7 (semver) Affected: 24.2 , < 24.2R2 (semver) Affected: 24.4 , < 24.4R2 (semver)

Date Public

2026-04-08 16:00

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-3P5V-CHX4-4483

CVE-2026-33774 (GCVE-0-2026-33774)

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