CVE-2021-0205

Descriptions du CVE

Junos OS: MX Series: Dynamic filter fails to match IPv6 prefix

When the "Intrusion Detection Service" (IDS) feature is configured on Juniper Networks MX series with a dynamic firewall filter using IPv6 source or destination prefix, it may incorrectly match the prefix as /32, causing the filter to block unexpected traffic. This issue affects only IPv6 prefixes when used as source and destination. This issue affects MX Series devices using MS-MPC, MS-MIC or MS-SPC3 service cards with IDS service configured. This issue affects: Juniper Networks Junos OS 17.3 versions prior to 17.3R3-S10 on MX Series; 17.4 versions prior to 17.4R3-S3 on MX Series; 18.1 versions prior to 18.1R3-S11 on MX Series; 18.2 versions prior to 18.2R3-S6 on MX Series; 18.3 versions prior to 18.3R3-S4 on MX Series; 18.4 versions prior to 18.4R3-S6 on MX Series; 19.1 versions prior to 19.1R2-S2, 19.1R3-S3 on MX Series; 19.2 versions prior to 19.2R3-S1 on MX Series; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1 on MX Series; 19.4 versions prior to 19.4R3 on MX Series; 20.1 versions prior to 20.1R2 on MX Series; 20.2 versions prior to 20.2R2 on MX Series;

Solutions du CVE

The following software releases have been updated to resolve this specific issue: Junos OS: 17.3R3-S10, 17.4R3-S3, 18.1R3-S11, 18.2R3-S6, 18.3R3-S4, 18.4R3-S6, 19.1R2-S2, 19.1R3-S3, 19.2R3-S1, 19.3R2-S5, 19.3R3-S1, 19.4R3, 20.1R2, 20.2R2, 20.3R1 and all subsequent releases.

Informations du CVE

Faiblesses connexes

CWE-ID	Nom de la faiblesse	Source
CWE-284	Improper Access Control The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Métriques

Métriques	Score	Gravité	CVSS Vecteur	Source
V3.1	5.8	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L More informations Base: Exploitabilty Metrics The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack Vector This metric reflects the context by which vulnerability exploitation is possible. Network The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). Attack Complexity This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Low Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component. Privileges Required This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. None The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack. User Interaction This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component. None The vulnerable system can be exploited without interaction from any user. Base: Scope Metrics The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope. Scope Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs. Changed An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities. Base: Impact Metrics The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve. Confidentiality Impact This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. None There is no loss of confidentiality within the impacted component. Integrity Impact This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. None There is no loss of integrity within the impacted component. Availability Impact This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. Low Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component. Temporal Metrics The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability. Environmental Metrics These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.
V2	4.3		AV:N/AC:M/Au:N/C:N/I:N/A:P	nvd@nist.gov

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Date	EPSS V0	EPSS V1	EPSS V2 (> 2022-02-04)	EPSS V3 (> 2025-03-07)	EPSS V4 (> 2025-03-17)
2021-04-18	0.42%	–	–	–	–
2021-09-05	–	0.42%	–	–	–
2021-12-26	–	0.42%	–	–	–
2022-01-09	–	1.84%	–	–	–
2022-01-16	–	1.84%	–	–	–
2022-02-06	–	–	4.5%	–	–
2022-03-13	–	–	4.5%	–	–
2022-04-03	–	–	0.89%	–	–
2022-04-24	–	–	0.89%	–	–
2022-07-17	–	–	0.89%	–	–
2022-10-09	–	–	0.89%	–	–
2023-02-19	–	–	0.89%	–	–
2023-03-12	–	–	–	0.08%	–
2023-09-10	–	–	–	0.08%	–
2023-10-01	–	–	–	0.09%	–
2024-02-11	–	–	–	0.09%	–
2024-04-14	–	–	–	0.09%	–
2024-06-02	–	–	–	0.09%	–
2024-06-16	–	–	–	0.09%	–
2024-08-04	–	–	–	0.09%	–
2024-08-11	–	–	–	0.09%	–
2024-11-10	–	–	–	0.09%	–
2024-12-22	–	–	–	0.11%	–
2025-01-19	–	–	–	0.11%	–
2025-01-19	–	–	–	0.11%	–
2025-03-18	–	–	–	–	0.23%
2025-03-30	–	–	–	–	0.23%
2025-04-15	–	–	–	–	0.23%
2025-04-15	–	–	–	–	0.23,%

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

EPSS First.org

Date	Percentile
2021-04-18	–
2021-09-05	26%
2021-12-26	27%
2022-01-09	47%
2022-01-16	48%
2022-02-06	74%
2022-03-13	75%
2022-04-03	24%
2022-04-24	25%
2022-07-17	26%
2022-10-09	27%
2023-02-19	28%
2023-03-12	33%
2023-09-10	34%
2023-10-01	39%
2024-02-11	38%
2024-04-14	39%
2024-06-02	39%
2024-06-16	4%
2024-08-04	39%
2024-08-11	4%
2024-11-10	41%
2024-12-22	44%
2025-01-19	45%
2025-01-19	45%
2025-03-18	44%
2025-03-30	43%
2025-04-15	46%
2025-04-15	46%

Products Mentioned

Configuraton 0

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)

Juniper>>Junos >> Version 17.3

Juniper>>Junos >> Version 17.3 (Open CPE detail)