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Description

A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart. This issue affects Junos OS on SRX and MX Series: * all versions before 22.4R3-S7, * 23.2 versions before 23.2R2-S3, * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R2.

PUBLISHED Reserved 2026-01-05 | Published 2026-01-15 | Updated 2026-01-15 | Assigner juniper




HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

HIGH: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M

Problem types

CWE-415 Double Free

Product status

Default status
unaffected

Any version before 22.4R3-S7
affected

23.2 (semver) before 23.2R2-S3
affected

23.4 (semver) before 23.4R2-S4
affected

24.2 (semver) before 24.2R2
affected

References

supportportal.juniper.net/JSA106018 vendor-advisory

kb.juniper.net/JSA106018 vendor-advisory

cve.org (CVE-2026-21918)

nvd.nist.gov (CVE-2026-21918)

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