CVE-2026-21917: Junos OS: SRX Series: Specifically malformed SSL packet causes FPC crash
Juniper Networks · Junos OS
Vendor fix available · Affected: Juniper Networks Junos OS · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 35% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- Juniper Networks · Junos OSfrom 23.2R2-S2 before 23.2R2-S5; from 23.4R2-S1 before 23.4R2-S5; from 24.2 before 24.2R2-S2; from 24.4 before 24.4R1-S3, 24.4R2
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- Juniper Networks
- Published
- January 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-21917 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.