Vulnerability-Lookup

GHSA-QXMF-M5MX-7VX7

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

Details

On SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.

This issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.

This issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:

all versions before 21.2R3-S10,
from 21.4 before 21.4R3-S12,
from 22.4 before 22.4R3-S8,
from 23.2 before 23.2R2-S5,
from 23.4 before 23.4R2-S6,
from 24.2 before 24.2R2-S3,
from 24.4 before 24.4R2-S1,
from 25.2 before 25.2R1-S1, 25.2R2.

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/V:C/RE:M/U:Amber

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-21905"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-15T21:16:05Z",
    "severity": "HIGH"
  },
  "details": "A Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027) vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).\n\nOn SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.\n\nThis issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.\n\nThis issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:\n\n\n\n  *  all versions before 21.2R3-S10,\u00a0\n  *  from 21.4 before 21.4R3-S12,\u00a0\n  *  from 22.4 before 22.4R3-S8,\u00a0\n  *  from 23.2 before 23.2R2-S5,\u00a0\n  *  from 23.4 before 23.4R2-S6,\u00a0\n  *  from 24.2 before 24.2R2-S3,\u00a0\n  *  from 24.4 before 24.4R2-S1,\u00a0\n  *  from 25.2 before 25.2R1-S1, 25.2R2.",
  "id": "GHSA-qxmf-m5mx-7vx7",
  "modified": "2026-01-15T21:31:48Z",
  "published": "2026-01-15T21:31:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21905"
    },
    {
      "type": "WEB",
      "url": "https://kb.juniper.net/JSA106004"
    },
    {
      "type": "WEB",
      "url": "https://supportportal.juniper.net/JSA106004"
    }
  ],
  "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:C/RE:M/U:Amber",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-21905 (GCVE-0-2026-21905)

Vulnerability from cvelistv5 – Published: 2026-01-15 20:19 – Updated: 2026-01-16 16:26

Title

Junos OS: SRX Series, MX Series with MX-SPC3 or MS-MPC: Receipt of multiple specific SIP messages results in flow management process crash

Summary

A Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS). On SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC. This issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue. This issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC: * all versions before 21.2R3-S10, * from 21.4 before 21.4R3-S12, * from 22.4 before 22.4R3-S8, * from 23.2 before 23.2R2-S5, * from 23.4 before 23.4R2-S6, * from 24.2 before 24.2R2-S3, * from 24.4 before 24.4R2-S1, * from 25.2 before 25.2R1-S1, 25.2R2.

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/V:C/RE:M/U:Amber

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-16 16:25 UTC

CWE

CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Assigner

juniper mitre root

References

2 references

URL	Tags
https://supportportal.juniper.net/JSA106004	vendor-advisory
https://kb.juniper.net/JSA106004	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Juniper Networks	Junos OS	Affected: 0 , < 21.2R3-S10 (semver) Affected: 21.4 , < 21.4R3-S12 (semver) Affected: 22.4 , < 22.4R3-S8 (semver) Affected: 23.2 , < 23.2R2-S5 (semver) Affected: 23.4 , < 23.4R2-S6 (semver) Affected: 24.2 , < 24.2R2-S3 (semver) Affected: 24.4 , < 24.4R2-S1 (semver) Affected: 25.2 , < 25.2R1-S1, 25.2R2 (semver)

Date Public

2026-01-14 17:00

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-21905",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-16T16:25:54.871316Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-16T16:26:02.071Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "SRX Series",
            "MX Series with MX-SPC3",
            "MX Series with MS-MPC"
          ],
          "product": "Junos OS",
          "vendor": "Juniper Networks",
          "versions": [
            {
              "lessThan": "21.2R3-S10",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "21.4R3-S12",
              "status": "affected",
              "version": "21.4",
              "versionType": "semver"
            },
            {
              "lessThan": "22.4R3-S8",
              "status": "affected",
              "version": "22.4",
              "versionType": "semver"
            },
            {
              "lessThan": "23.2R2-S5",
              "status": "affected",
              "version": "23.2",
              "versionType": "semver"
            },
            {
              "lessThan": "23.4R2-S6",
              "status": "affected",
              "version": "23.4",
              "versionType": "semver"
            },
            {
              "lessThan": "24.2R2-S3",
              "status": "affected",
              "version": "24.2",
              "versionType": "semver"
            },
            {
              "lessThan": "24.4R2-S1",
              "status": "affected",
              "version": "24.4",
              "versionType": "semver"
            },
            {
              "lessThan": "25.2R1-S1, 25.2R2",
              "status": "affected",
              "version": "25.2",
              "versionType": "semver"
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          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "The SIP ALG must be enabled to be vulnerable to this issue. The SIP ALG is enabled by default on MX-SPC3 and some SRX Series platforms. For other platforms, the following configuration is required:\u003cbr\u003e\u003cbr\u003e\n\n\u003ctt\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e[security alg sip enable]\u003c/span\u003e\u003c/tt\u003e\u003cbr\u003e\n\u003cbr\u003eOn SRX Series and MX Series with MX-SPC3, the SIP ALG status can be confirmed via the \u0027show security alg status\u0027 command:\u003cbr\u003e\n\u003cbr\u003e\n\u003ctt\u003euser@junos\u0026gt; show security alg status\u003c/tt\u003e\u003cbr\u003e\n\u003ctt\u003eALG Status:\u003c/tt\u003e\u003cbr\u003e\n...\u003cbr\u003e\n\u003ctt\u003e\u0026nbsp; SIP  \u0026nbsp; \u0026nbsp; : Enabled\u003c/tt\u003e\u003cbr\u003e"
            }
          ],
          "value": "The SIP ALG must be enabled to be vulnerable to this issue. The SIP ALG is enabled by default on MX-SPC3 and some SRX Series platforms. For other platforms, the following configuration is required:\n\n\n\n[security alg sip enable]\n\n\nOn SRX Series and MX Series with MX-SPC3, the SIP ALG status can be confirmed via the \u0027show security alg status\u0027 command:\n\n\n\nuser@junos\u003e show security alg status\n\nALG Status:\n\n...\n\n\u00a0 SIP  \u00a0 \u00a0 : Enabled"
        }
      ],
      "datePublic": "2026-01-14T17:00:00.000Z",
      "descriptions": [
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          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "A Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027) vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).\u003cbr\u003e\u003cbr\u003eOn SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.\u003cbr\u003e\u003cbr\u003eThis issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.\u003cbr\u003e\u003cbr\u003e\u003cp\u003eThis issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cul\u003e\u003cli\u003eall versions before 21.2R3-S10,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 21.4 before 21.4R3-S12,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 22.4 before 22.4R3-S8,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 23.2 before 23.2R2-S5,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 23.4 before 23.4R2-S6,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 24.2 before 24.2R2-S3,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 24.4 before 24.4R2-S1,\u0026nbsp;\u003c/li\u003e\u003cli\u003efrom 25.2 before 25.2R1-S1, 25.2R2.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003e\u003c/p\u003e"
            }
          ],
          "value": "A Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027) vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS).\n\nOn SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC.\n\nThis issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue.\n\nThis issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC:\n\n\n\n  *  all versions before 21.2R3-S10,\u00a0\n  *  from 21.4 before 21.4R3-S12,\u00a0\n  *  from 22.4 before 22.4R3-S8,\u00a0\n  *  from 23.2 before 23.2R2-S5,\u00a0\n  *  from 23.4 before 23.4R2-S6,\u00a0\n  *  from 24.2 before 24.2R2-S3,\u00a0\n  *  from 24.4 before 24.4R2-S1,\u00a0\n  *  from 25.2 before 25.2R1-S1, 25.2R2."
        }
      ],
      "exploits": [
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          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
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            "vulnerabilityResponseEffort": "MODERATE"
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          "format": "CVSS",
          "scenarios": [
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          "descriptions": [
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        "dateUpdated": "2026-01-15T20:19:22.158Z",
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        "advisory": "JSA106004",
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        "discovery": "USER"
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      "title": "Junos OS: SRX Series, MX Series with MX-SPC3 or MS-MPC: Receipt of multiple specific SIP messages results in flow management process crash",
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          "supportingMedia": [
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              "value": "Where practical, use a firewall filter to limit SIP traffic over TCP.\u003cbr\u003e\u003cbr\u003eAlternately, if the SIP ALG is not required, it can be explicitly disabled on SRX Series and MX Series with MX-SPC3 via:\u003cbr\u003e\u003cbr\u003e\u003ctt\u003e# set security alg sip disable\u003c/tt\u003e\u003cbr\u003e\u003cbr\u003e"
            }
          ],
          "value": "Where practical, use a firewall filter to limit SIP traffic over TCP.\n\nAlternately, if the SIP ALG is not required, it can be explicitly disabled on SRX Series and MX Series with MX-SPC3 via:\n\n# set security alg sip disable"
        }
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    "assignerShortName": "juniper",
    "cveId": "CVE-2026-21905",
    "datePublished": "2026-01-15T20:19:22.158Z",
    "dateReserved": "2026-01-05T17:32:48.710Z",
    "dateUpdated": "2026-01-16T16:26:02.071Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
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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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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