CVE-2023-36838: Junos OS: SRX Series: A flowd core occurs when running a low privileged CLI command

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-14 · updated 2026-06-17
Weakness: CWE-125

Description

An Out-of-bounds Read vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX Series allows a local, authenticated attacker with low privileges, to cause a Denial of Service (DoS). If a low privileged user executes a specific CLI command, flowd which is responsible for traffic forwarding in SRX crashes and generates a core dump. This will cause temporary traffic interruption until the flowd process is restarted automatically. Continued execution of this command will lead to a sustained DoS. This issue affects Juniper Networks Junos OS on SRX Series: All versions prior to 20.2R3-S7; 20.3 version 20.3R1 and later versions; 20.4 versions prior to 20.4R3-S6; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S4; 21.3 versions prior to 21.3R3-S4; 21.4 versions prior to 21.4R3-S3; 22.1 versions prior to 22.1R3-S1; 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R2; 22.4 versions prior to 22.4R1-S1, 22.4R2.

Affected products

Juniper Junos OS: before 20.2; 20.2, 20.2-r1, 20.2-r1-s1, 20.2-r1-s2, 20.2-r1-s3, 20.2-r2 (+94) — fixed in 20.2

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.2. Check the vendor advisory for mitigations.

References

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