CVE-2023-44186

CVE-2023-44186 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-755.

Key facts

Description

An Improper Handling of Exceptional Conditions vulnerability in AS PATH processing of Juniper Networks Junos OS and Junos OS Evolved allows an attacker to send a BGP update message with an AS PATH containing a large number of 4-byte ASes, leading to a Denial of Service (DoS). Continued receipt and processing of these BGP updates will create a sustained Denial of Service (DoS) condition. This issue is hit when the router has Non-Stop Routing (NSR) enabled, has a non-4-byte-AS capable BGP neighbor, receives a BGP update message with a prefix that includes a long AS PATH containing large number of 4-byte ASes, and has to advertise the prefix towards the non-4-byte-AS capable BGP neighbor. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. This issue affects: Juniper Networks Junos OS: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3-S1; * 22.4 versions prior to 22.4R2-S1, 22.4R3. Juniper Networks Junos OS Evolved * All versions prior to 20.4R3-S8-EVO; * 21.1 versions 21.1R1-EVO and later; * 21.2 versions prior to 21.2R3-S6-EVO; * 21.3 versions prior to 21.3R3-S5-EVO; * 21.4 versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S4-EVO; * 22.2 versions prior to 22.2R3-S2-EVO; * 22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO; * 22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO.

Frequently asked questions

What is CVE-2023-44186?
An Improper Handling of Exceptional Conditions vulnerability in AS PATH processing of Juniper Networks Junos OS and Junos OS Evolved allows an attacker to send a BGP update message with an AS PATH containing a large number of 4-byte ASes, leading to a Denial of Service (DoS). Continued receipt and processing of these BGP updates will create a sustained Denial of Service (DoS) condition. This issue is hit when the router has Non-Stop Routing (NSR) enabled, has a non-4-byte-AS capable BGP neighbor, receives a BGP update message with a prefix that includes a long AS PATH containing large number of 4-byte ASes, and has to advertise the prefix towards the non-4-byte-AS capable BGP neighbor. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. This issue affects: Juniper Networks Junos OS: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3-S1; * 22.4 versions prior to 22.4R2-S1, 22.4R3. Juniper Networks Junos OS Evolved * All versions prior to 20.4R3-S8-EVO; * 21.1 versions 21.1R1-EVO and later; * 21.2 versions prior to 21.2R3-S6-EVO; * 21.3 versions prior to 21.3R3-S5-EVO; * 21.4 versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S4-EVO; * 22.2 versions prior to 22.2R3-S2-EVO; * 22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO; * 22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO.
How severe is CVE-2023-44186?
CVE-2023-44186 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-2023-44186 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-2023-44186?
CVE-2023-44186 primarily affects Juniper Junos. In total, 183 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-44186?
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.
When was CVE-2023-44186 published?
CVE-2023-44186 was published on 2023-10-11 and last updated on 2026-06-17.

References

Affected products (183)

More vulnerabilities in Juniper Junos

All CVEs affecting Juniper Junos →

Other CWE-755 (Improper Handling of Exceptional Conditions) vulnerabilities

Browse all CWE-755 (Improper Handling of Exceptional Conditions) vulnerabilities →