CVE-2026-21918 is a Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series platforms. An unauthenticated, network-based attacker can trigger this flaw by sending a specific sequence of packets during TCP session establishment, causing flowd to crash and the FPC to restart, leading to a Denial-of-Service (DoS). With a CVSS score of 7.5 (HIGH), this vulnerability is easily exploitable over the network with low attack complexity and no user interaction required, resulting in a high impact on availability. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 0, < 22.4R3-S7CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
>= 23.2, < 23.2R2-S3CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
>= 23.4, < 23.4R2-S4CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
>= 24.2, < 24.2R2CPE match | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* | ||
< 22.4CPE matchmatch criteria | cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* |
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
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The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.