CVE-2026-21917 describes an Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering module of Juniper Networks Junos OS on SRX Series devices. An unauthenticated, network-based attacker can exploit this by sending a specially malformed SSL packet, causing a Denial-of-Service (DoS) through an FPC crash and restart. This vulnerability has a CVSS score of 7.5 (HIGH), indicating a severe impact with no confidentiality or integrity compromise but high availability impact. While there is no known active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community discussion, suggesting awareness among security researchers.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 23.2R2-S2, < 23.2R2-S5CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
>= 23.4R2-S1, < 23.4R2-S5CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
>= 24.2, < 24.2R2-S2CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
23.2CPE matchmatch criteria | cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:* | ||
23.2CPE matchmatch criteria | cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:* |
CVSS version used by this source: 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:X
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.