PT-2026-3129 · Juniper Networks · Junos Srx Series

Published 2026-01-14 · Updated 2026-01-16 · CVE-2026-21917

Positive Technologies (AI Summary)

CVSS v2.0

7.8

High

Base vector

AV:N/AC:L/Au:N/C:N/I:N/A:C

Name of the Vulnerable Software and Affected Versions Juniper Networks Junos OS on SRX Series versions 23.2R2-S2 through 23.2R2-S4 Juniper Networks Junos OS on SRX Series versions 23.4R2-S1 through 23.4R2-S4 Juniper Networks Junos OS on SRX Series versions prior to 24.2R2-S2 Juniper Networks Junos OS on SRX Series versions prior to 24.4R1-S3

Description An improper validation of syntactic correctness of input exists in the Web-Filtering module. This can allow an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). Specifically, if an SRX device configured for UTM Web-Filtering receives a malformed SSL packet, it can cause an FPC crash and restart.

Recommendations Upgrade to Junos OS version 23.2R2-S5 or later. Upgrade to Junos OS version 23.4R2-S5 or later. Upgrade to Junos OS version 24.2R2-S2 or later. Upgrade to Junos OS version 24.4R1-S3 or later.

Fix

Weakness Enumeration

CWE-1286

Related Identifiers

BDU:2026-00584

CVE-2026-21917

Affected Products

Junos Srx Series

References · 8

• https://supportportal.juniper.net/JSA105996 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-21917 · Security Note
• https://kb.juniper.net/JSA105996 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-00584 · Security Note
• https://osv.dev/vulnerability/CVE-2026-21917 · Vendor Advisory
• https://twitter.com/RedPacketSec/status/2011962646887583920 · Twitter Post
• https://supportportal.juniper.net/s/article/2026-01-Security-Bulletin-Junos-OS-SRX-Series-Specifically-malformed-SSL-packet-causes-FPC-crash-CVE-2026-21917 · Note
• https://twitter.com/CVEnew/status/2011926037362561534 · Twitter Post