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CVE-2024-21601

Junos OS: SRX Series: Due to an error in processing TCP events flowd will crash

MEDIUM
5.9
CVSS Score
Published: January 12, 2024 at 12:53 AM UTC
Updated: June 17, 2026 at 07:09 AM UTC
1 product affected across 1 vendorJunos

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the Flow-processing Daemon (flowd) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (Dos). On SRX Series devices when two different threads try to simultaneously process a queue which is used for TCP events flowd will crash. One of these threads can not be triggered externally, so the exploitation of this race condition is outside the attackers direct control. Continued exploitation of this issue will lead to a sustained DoS. This issue affects Juniper Networks Junos OS: * 21.2 versions earlier than 21.2R3-S5; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S4; * 22.1 versions earlier than 22.1R3-S3; * 22.2 versions earlier than 22.2R3-S1; * 22.3 versions earlier than 22.3R2-S2, 22.3R3; * 22.4 versions earlier than 22.4R2-S1, 22.4R3. This issue does not affect Juniper Networks Junos OS versions earlier than 21.2R1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos· Juniper Networks
95%
21.2 ≤ v < 21.2R3-S521.3 ≤ v < 21.3R3-S521.4 ≤ v < 21.4R3-S422.1 ≤ v < 22.1R3-S322.2 ≤ v < 22.2R3-S122.3 ≤ v < 22.3R2-S2, 22.3R322.4 ≤ v < 22.4R2-S1, 22.4R321.221.2 r121.2 r1-s121.2 r1-s221.2 r221.2 r2-s121.2 r2-s221.2 r321.2 r3-s121.2 r3-s221.2 r3-s321.2 r3-s421.321.3 r121.3 r1-s121.3 r1-s221.3 r221.3 r2-s121.3 r2-s221.3 r321.3 r3-s121.3 r3-s221.3 r3-s321.3 r3-s421.421.4 r121.4 r1-s121.4 r1-s221.4 r221.4 r2-s121.4 r2-s221.4 r321.4 r3-s121.4 r3-s221.4 r3-s322.122.1 r122.1 r1-s122.1 r1-s222.1 r222.1 r2-s122.1 r2-s222.1 r322.1 r3-s122.1 r3-s222.222.2 r122.2 r1-s122.2 r1-s222.2 r222.2 r2-s122.2 r2-s222.2 r322.322.3 r122.3 r1-s122.3 r1-s222.3 r222.3 r2-s122.422.4 r122.4 r1-s122.4 r1-s222.4 r2
Affected range stops below 21.2R3-S5, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.3R3-S5, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.4R3-S4, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.1R3-S3, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.2R3-S1, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.3R2-S2, 22.3R3, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.4R2-S1, 22.4R3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

Vendor Advisory
Source: [email protected]
https://supportportal.juniper.net/JSA75742
Technical DescriptionThird Party Advisory
Source: [email protected]
https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMjuniper
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-362

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