CVE-2024-21593
Juniper Junos 21.4 … 23.2
Raw vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2024-21593 is a high-severity Improper Check or Handling of Exceptional Conditions (CWE-703) vulnerability in Juniper Junos. Its CVSS base score is 7.1 (High).
Operationally, ranked at the 21th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-24 (Fail in Known State) and SI-17 (Fail-safe Procedures) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-19241
Vulnerability Data
An Improper Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). If an attacker sends…
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a specific MPLS packet, which upon processing, causes an internal loop, that leads to a PFE crash and restart. Continued receipt of these packets leads to a sustained Denial of Service (DoS) condition. Circuit cross-connect (CCC) needs to be configured on the device for it to be affected by this issue. This issue only affects MX Series with MPC10, MPC11, LC9600, and MX304. This issue affects: Juniper Networks Junos OS 21.4 versions from 21.4R3 earlier than 21.4R3-S5; 22.2 versions from 22.2R2 earlier than 22.2R3-S2; 22.3 versions from 22.3R1 earlier than 22.3R2-S2; 22.3 versions from 22.3R3 earlier than 22.3R3-S1 22.4 versions from 22.4R1 earlier than 22.4R2-S2, 22.4R3; 23.2 versions earlier than 23.2R1-S1, 23.2R2.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforces failure to a known state while preserving required properties, limiting impact of unhandled exceptions.
Mandates explicit fail-safe procedures triggered by indicated failures, structurally preventing unhandled exceptional conditions.
Requires application of security engineering principles that include robust exception and error handling during design.
Requires generation of safe, actionable error messages that directly addresses proper handling of exceptional conditions.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
A.8.26 only requires that security requirements (including resilience against attacks like SQL injection) be identified and specified during development or acquisition; it does not itself remove, fix, or eliminate any exceptional-condition handling defects already present in code.
A.8.28 mandates secure coding practices, principles, defect removal during coding/review, and prohibiting insecure techniques that directly produce improper exception handling; this removes most instances of the first-party code defect, with a bounded remainder in incomplete adoption or edge-case defects not captured by the baseline.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-703, a pillar-level weakness, and none of its children carries one either.