CVE-2021-0259
Published: 22 April 2021
Summary
CVE-2021-0259 is a high-severity Improper Handling of Exceptional Conditions (CWE-755) vulnerability in Juniper Junos. Its CVSS base score is 7.4 (High).
Operationally, ranked at the 28.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-2878
Vulnerability details
Due to a vulnerability in DDoS protection in Juniper Networks Junos OS and Junos OS Evolved on QFX5K Series switches in a VXLAN configuration, instability might be experienced in the underlay network as a consequence of exceeding the default ddos-protection…
more
aggregate threshold. If an attacker on a client device on the overlay network sends a high volume of specific, legitimate traffic in the overlay network, due to an improperly detected DDoS violation, the leaf might not process certain L2 traffic, sent by spines in the underlay network. Continued receipt and processing of the high volume traffic will sustain the Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS on QFX5K Series: 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S6; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2; 20.3 versions prior to 20.3R1-S2, 20.3R2. Juniper Networks Junos OS Evolved on QFX5220: All versions prior to 20.3R2-EVO.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Provides defined handling (alert and additional actions) for the exceptional condition of audit logging failure.
Supplies a concrete handling action (safe mode) for exceptional conditions, mitigating risks from improper or absent handling that could allow continued attacks.
By preparing users for contingency scenarios, the control promotes proper handling of exceptional conditions instead of default or unsafe behaviors.
An updated contingency plan defines current actions for exceptional conditions, reducing the window for attackers to exploit improper handling leading to system failure.
Procedures ensure proper handling of exceptional conditions to support effective incident response.
Incident response testing confirms proper handling of exceptional conditions to limit exploit impact.
Gives users guidance on incident handling, reducing improper handling of exceptional conditions that could stem from exploited weaknesses.
Enforces structured response to exceptional conditions so the system cannot remain in an unsafe state.