High [CVE-2026-21917] Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering module of Juniper Networks Junos OS…
This high-severity Juniper Networks advisory covers CVE-2026-21917 affecting Junos, Junos OS, SRX.
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Summary
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,
Earlier versions of Junos are also affected, but no fix is available.
- 23.2
- 23.4
- 24.2
- 24.4
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
- 23.2R2-S5
- 23.4R2-S5
- 24.2R2-S2
- 24.4R1-S3
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation
Upgrade to a fixed release: 23.2R2-S5, 23.4R2-S5, 24.2R2-S2, 24.4R1-S3. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Discussion(0)
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