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.