CVE-2024-39526

CVE-2024-39526 is a medium-severity vulnerability in Juniper Junos Os Evolved with a CVSS 3.x base score of 6.5. 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 packet processing of Juniper Networks Junos OS on MX Series with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C lines cards, MX304 devices, and Juniper Networks Junos OS Evolved on PTX Series, allows an attacker sending malformed DHCP packets to cause ingress packet processing to stop, leading to a Denial of Service (DoS).  Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition. This issue only occurs if DHCP snooping is enabled. See configuration below. This issue can be detected using following commands. Their output will display the interface status going down: user@device>show interfaces <if--x/x/x> user@device>show log messages | match <if--x/x/x> user@device>show log messages ==> will display the "[Error] Wedge-Detect : Host Loopback Wedge Detected: PFE: no," logs. This issue affects: Junos OS on MX Series with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C line cards, and MX304: * All versions before 21.2R3-S7, * from 21.4 before 21.4R3-S6, * from 22.2 before 22.2R3-S3, * all versions of 22.3, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2; Junos OS Evolved on PTX Series: * from 19.3R1-EVO before 21.2R3-S8-EVO, * from 21.4-EVO before 21.4R3-S7-EVO, * from 22.1-EVO before 22.1R3-S6-EVO, * from 22.2-EVO before 22.2R3-S5-EVO, * from 22.3-EVO before 22.3R3-S3-EVO, * from 22.4-EVO before 22.4R3-S1-EVO, * from 23.2-EVO before 23.2R2-S2-EVO, * from 23.4-EVO before 23.4R2-EVO. Junos OS Evolved releases prior to 19.3R1-EVO are unaffected by this vulnerability

Frequently asked questions

What is CVE-2024-39526?
An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS on MX Series with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C lines cards, MX304 devices, and Juniper Networks Junos OS Evolved on PTX Series, allows an attacker sending malformed DHCP packets to cause ingress packet processing to stop, leading to a Denial of Service (DoS).  Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition. This issue only occurs if DHCP snooping is enabled. See configuration below. This issue can be detected using following commands. Their output will display the interface status going down: user@device>show interfaces <if--x/x/x> user@device>show log messages | match <if--x/x/x> user@device>show log messages ==> will display the "[Error] Wedge-Detect : Host Loopback Wedge Detected: PFE: no," logs. This issue affects: Junos OS on MX Series with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C line cards, and MX304: * All versions before 21.2R3-S7, * from 21.4 before 21.4R3-S6, * from 22.2 before 22.2R3-S3, * all versions of 22.3, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2; Junos OS Evolved on PTX Series: * from 19.3R1-EVO before 21.2R3-S8-EVO, * from 21.4-EVO before 21.4R3-S7-EVO, * from 22.1-EVO before 22.1R3-S6-EVO, * from 22.2-EVO before 22.2R3-S5-EVO, * from 22.3-EVO before 22.3R3-S3-EVO, * from 22.4-EVO before 22.4R3-S1-EVO, * from 23.2-EVO before 23.2R2-S2-EVO, * from 23.4-EVO before 23.4R2-EVO. Junos OS Evolved releases prior to 19.3R1-EVO are unaffected by this vulnerability
How severe is CVE-2024-39526?
CVE-2024-39526 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-39526 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-39526?
CVE-2024-39526 primarily affects Juniper Junos Os Evolved. In total, 138 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-39526?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-39526 have an EU (EUVD) identifier?
Yes. CVE-2024-39526 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-38052.
When was CVE-2024-39526 published?
CVE-2024-39526 was published on 2024-10-11 and last updated on 2026-06-17.

References

Affected products (138)

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