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HIGH · 7.5

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...

Vulnerability Description

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.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
JuniperJunos23.2
JuniperSrx1500-
JuniperSrx1600-
JuniperSrx2300-
JuniperSrx300-
JuniperSrx320-
JuniperSrx340-
JuniperSrx345-
JuniperSrx380-
JuniperSrx4100-
JuniperSrx4120-
JuniperSrx4200-
JuniperSrx4300-
JuniperSrx4600-
JuniperSrx4700-
JuniperSrx5400-
JuniperSrx5600-
JuniperSrx5800-

Related Weaknesses (CWE)

CWE-1286

References

FAQ

What is CVE-2026-21917?

CVE-2026-21917 is a vulnerability with a CVSS score of 7.5 (HIGH). 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...

How severe is CVE-2026-21917?

CVE-2026-21917 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-21917?

Check the references section above for vendor advisories and patch information. Affected products include: Juniper Junos, Juniper Srx1500, Juniper Srx1600, Juniper Srx2300, Juniper Srx300.