Vulnerability-Lookup

GHSA-VJ9C-H3R9-JWRF

Vulnerability from github – Published: 2026-01-15 21:31 – Updated: 2026-01-15 21:31

Details

An Unchecked Return Value vulnerability in the DNS module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).

If an SRX Series device configured for DNS processing, receives a specifically formatted DNS request flowd will crash and restart, which causes a service interruption until the process has recovered.

This issue affects Junos OS on SRX Series:

23.4 versions before 23.4R2-S5,
24.2 versions before 24.2R2-S1,
24.4 versions before 24.4R2.

This issue does not affect Junos OS versions before 23.4R1.

Severity ?

7.5 (High)


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

8.7 (High)


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

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-21920"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-252"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-15T21:16:08Z",
    "severity": "HIGH"
  },
  "details": "An Unchecked Return Value vulnerability in the DNS module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).\n\n\n\n\nIf an SRX Series device configured for DNS processing, receives a specifically formatted DNS request flowd will crash and restart, which causes a service interruption until the process has recovered.\n\nThis issue affects Junos OS on SRX Series:\n\n\n\n  *  23.4 versions before 23.4R2-S5,\n  *  24.2 versions before 24.2R2-S1,\n  *  24.4 versions before 24.4R2.\n\n\n\n\n\n\nThis issue does not affect Junos OS versions before 23.4R1.",
  "id": "GHSA-vj9c-h3r9-jwrf",
  "modified": "2026-01-15T21:31:48Z",
  "published": "2026-01-15T21:31:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21920"
    },
    {
      "type": "WEB",
      "url": "https://kb.juniper.net/JSA106020"
    },
    {
      "type": "WEB",
      "url": "https://supportportal.juniper.net/JSA106020"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/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:A/V:X/RE:M/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-21920 (GCVE-0-2026-21920)

Vulnerability from cvelistv5 – Published: 2026-01-15 20:28 – Updated: 2026-01-15 20:59

Title

Junos OS: SRX Series: If a specific request is processed by the DNS subsystem flowd will crash

Summary

An Unchecked Return Value vulnerability in the DNS module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). If an SRX Series device configured for DNS processing, receives a specifically formatted DNS request flowd will crash and restart, which causes a service interruption until the process has recovered. This issue affects Junos OS on SRX Series: * 23.4 versions before 23.4R2-S5, * 24.2 versions before 24.2R2-S1, * 24.4 versions before 24.4R2. This issue does not affect Junos OS versions before 23.4R1.

Severity ?

7.5 (High)


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

8.7 (High)


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

CWE

CWE-252 - Unchecked Return Value

Assigner

juniper

References

URL

Tags

	https://supportportal.juniper.net/JSA106020	vendor-advisory
	https://kb.juniper.net/JSA106020	vendor-advisory

Impacted products

	Vendor	Product	Version
	Juniper Networks	Junos OS	Affected: 23.4 , < 23.4R2-S5 (semver) Affected: 24.2 , < 24.2R2-S1 (semver) Affected: 24.4 , < 24.4R2 (semver) Unaffected: 0 , < 23.4R1 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-21920",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-15T20:58:50.543674Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-15T20:59:21.070Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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        {
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          "platforms": [
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          ],
          "product": "Junos OS",
          "vendor": "Juniper Networks",
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              "status": "affected",
              "version": "23.4",
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              "status": "affected",
              "version": "24.2",
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          "lang": "en",
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        }
      ],
      "datePublic": "2026-01-14T17:00:00.000Z",
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          "scenarios": [
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Sightings

Author	Source	Type	Date

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-VJ9C-H3R9-JWRF

CVE-2026-21920 (GCVE-0-2026-21920)

Tags

Sightings

Nomenclature