Vulnerability Details CVE-2026-21917
An Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering 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 device configured for UTM Web-Filtering receives a specifically malformed SSL packet, this will cause an FPC crash and restart.
This issue affects Junos OS on SRX Series:
* 23.2 versions from 23.2R2-S2 before 23.2R2-S5,
* 23.4 versions from 23.4R2-S1 before 23.4R2-S5,
* 24.2 versions before 24.2R2-S2,
* 24.4 versions before 24.4R1-S3, 24.4R2.
Earlier versions of Junos are also affected, but no fix is available.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 21.6%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-21917
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cpe:2.3:h:juniper:srx1500:-
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cpe:2.3:h:juniper:srx1600:-
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cpe:2.3:h:juniper:srx2300:-
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cpe:2.3:h:juniper:srx300:-
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cpe:2.3:h:juniper:srx320:-
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cpe:2.3:h:juniper:srx340:-
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cpe:2.3:h:juniper:srx345:-
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cpe:2.3:h:juniper:srx380:-
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cpe:2.3:h:juniper:srx4100:-
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cpe:2.3:h:juniper:srx4120:-
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cpe:2.3:h:juniper:srx4200:-
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cpe:2.3:h:juniper:srx4300:-
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cpe:2.3:h:juniper:srx4600:-
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cpe:2.3:h:juniper:srx4700:-
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cpe:2.3:h:juniper:srx5400:-
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cpe:2.3:h:juniper:srx5600:-
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cpe:2.3:h:juniper:srx5800:-
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cpe:2.3:o:juniper:junos:23.2
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cpe:2.3:o:juniper:junos:23.4
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cpe:2.3:o:juniper:junos:24.2
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cpe:2.3:o:juniper:junos:24.4