How severe is CVE-2024-21616?

CVE-2024-21616 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-2024-21616 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-21616?

CVE-2024-21616 primarily affects Juniper Junos. In total, 74 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-21616?

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-2024-21616 have an EU (EUVD) identifier?

Yes. CVE-2024-21616 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-19264.

When was CVE-2024-21616 published?

CVE-2024-21616 was published on 2024-01-12 and last updated on 2026-06-17.

CVE-2024-21616

CVE-2024-21616 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-1286.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-19264
Weakness: CWE-1286
Affected product: Juniper Junos
Published: 2024-01-12
Last modified: 2026-06-17

Description

An Improper Validation of Syntactic Correctness of Input vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On all Junos OS MX Series and SRX Series platforms, when SIP ALG is enabled, and a specific SIP packet is received and processed, NAT IP allocation fails for genuine traffic, which causes Denial of Service (DoS). Continuous receipt of this specific SIP ALG packet will cause a sustained DoS condition. NAT IP usage can be monitored by running the following command. user@srx> show security nat resource-usage source-pool <source_pool_name> Pool name: source_pool_name .. Address Factor-index Port-range Used Avail Total Usage X.X.X.X 0 Single Ports 50258 52342 62464 96% <<<<< - Alg Ports 0 2048 2048 0% This issue affects: Juniper Networks Junos OS on MX Series and SRX Series * All 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-S4; * 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; * 23.2 versions earlier than 23.2R1-S1, 23.2R2.

Frequently asked questions

What is CVE-2024-21616?: An Improper Validation of Syntactic Correctness of Input vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On all Junos OS MX Series and SRX Series platforms, when SIP ALG is enabled, and a specific SIP packet is received and processed, NAT IP allocation fails for genuine traffic, which causes Denial of Service (DoS). Continuous receipt of this specific SIP ALG packet will cause a sustained DoS condition. NAT IP usage can be monitored by running the following command. user@srx> show security nat resource-usage source-pool <source_pool_name> Pool name: source_pool_name .. Address Factor-index Port-range Used Avail Total Usage X.X.X.X 0 Single Ports 50258 52342 62464 96% <<<<< - Alg Ports 0 2048 2048 0% This issue affects: Juniper Networks Junos OS on MX Series and SRX Series * All 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-S4; * 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; * 23.2 versions earlier than 23.2R1-S1, 23.2R2.
How severe is CVE-2024-21616?: CVE-2024-21616 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-2024-21616 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-21616?: CVE-2024-21616 primarily affects Juniper Junos. In total, 74 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-21616?: 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-2024-21616 have an EU (EUVD) identifier?: Yes. CVE-2024-21616 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-19264.
When was CVE-2024-21616 published?: CVE-2024-21616 was published on 2024-01-12 and last updated on 2026-06-17.

References

Affected products (74)

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:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r2-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r2-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r3-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r3-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r3-s3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:21.4:r3-s4:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:22.1:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:22.1:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:22.1:r1-s1:*:*:*:*:*:*

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