FKIE_CVE-2026-21920
Vulnerability from fkie_nvd - Published: 2026-01-15 21:16 - Updated: 2026-01-23 18:51
Severity ?
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.
References
| URL | Tags | ||
|---|---|---|---|
| sirt@juniper.net | https://kb.juniper.net/JSA106020 | Vendor Advisory | |
| sirt@juniper.net | https://supportportal.juniper.net/JSA106020 | Vendor Advisory |
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 23.4 | |
| juniper | junos | 24.2 | |
| juniper | junos | 24.2 | |
| juniper | junos | 24.2 | |
| juniper | junos | 24.2 | |
| juniper | junos | 24.2 | |
| juniper | junos | 24.4 | |
| juniper | junos | 24.4 | |
| juniper | junos | 24.4 | |
| juniper | junos | 24.4 | |
| juniper | srx1500 | - | |
| juniper | srx1600 | - | |
| juniper | srx2300 | - | |
| juniper | srx300 | - | |
| juniper | srx320 | - | |
| juniper | srx340 | - | |
| juniper | srx345 | - | |
| juniper | srx380 | - | |
| juniper | srx4100 | - | |
| juniper | srx4120 | - | |
| juniper | srx4200 | - | |
| juniper | srx4300 | - | |
| juniper | srx4600 | - | |
| juniper | srx4700 | - | |
| juniper | srx5400 | - | |
| juniper | srx5600 | - | |
| juniper | srx5800 | - |
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"value": "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."
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"value": "Una vulnerabilidad de valor de retorno no verificado en el m\u00f3dulo DNS de Juniper Networks Junos OS en la serie SRX permite a un atacante no autenticado y basado en la red causar una denegaci\u00f3n de servicio (DoS).\n\nSi un dispositivo de la serie SRX configurado para el procesamiento de DNS recibe una solicitud DNS espec\u00edficamente formateada, flowd se bloquear\u00e1 y reiniciar\u00e1, lo que causa una interrupci\u00f3n del servicio hasta que el proceso se haya recuperado.\n\nEste problema afecta a Junos OS en la serie SRX:\n\n * versiones 23.4 anteriores a 23.4R2-S5,\n * versiones 24.2 anteriores a 24.2R2-S1,\n * versiones 24.4 anteriores a 24.4R2.\n\nEste problema no afecta a las versiones de Junos OS anteriores a 23.4R1."
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"id": "CVE-2026-21920",
"lastModified": "2026-01-23T18:51:59.987",
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"published": "2026-01-15T21:16:08.217",
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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.
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