How severe is CVE-2024-21606?

CVE-2024-21606 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2024-21606 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-21606?

CVE-2024-21606 primarily affects Juniper Junos. In total, 86 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-21606?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2024-21606 have an EU (EUVD) identifier?

Yes. CVE-2024-21606 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-19254.

When was CVE-2024-21606 published?

CVE-2024-21606 was published on 2024-01-12 and last updated on 2026-06-17.

CVE-2024-21606

CVE-2024-21606 is a high-severity vulnerability in Juniper Junos with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-415.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-19254
Weakness: CWE-415
Affected product: Juniper Junos
Published: 2024-01-12
Last modified: 2026-06-17

Description

A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). In a remote access VPN scenario, if a "tcp-encap-profile" is configured and a sequence of specific packets is received, a flowd crash and restart will be observed. This issue affects Juniper Networks Junos OS on SRX Series: * All versions earlier than 20.4R3-S8; * 21.2 versions earlier than 21.2R3-S6; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S3; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3.

Frequently asked questions

What is CVE-2024-21606?: A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). In a remote access VPN scenario, if a "tcp-encap-profile" is configured and a sequence of specific packets is received, a flowd crash and restart will be observed. This issue affects Juniper Networks Junos OS on SRX Series: * All versions earlier than 20.4R3-S8; * 21.2 versions earlier than 21.2R3-S6; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S3; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3.
How severe is CVE-2024-21606?: CVE-2024-21606 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-21606 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-21606?: CVE-2024-21606 primarily affects Juniper Junos. In total, 86 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-21606?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2024-21606 have an EU (EUVD) identifier?: Yes. CVE-2024-21606 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-19254.
When was CVE-2024-21606 published?: CVE-2024-21606 was published on 2024-01-12 and last updated on 2026-06-17.

References

Affected products (86)

cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r2-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r2-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s4:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s5:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s6:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:20.4:r3-s7:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r2-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r2-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r3-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r3-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r3-s3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r3-s4:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.2:r3-s5:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r2-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r2-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r3-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r3-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r3-s3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.3:r3-s4:*:*:*:*:*:*

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