How severe is CVE-2021-0276?

CVE-2021-0276 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-0276 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-0276?

CVE-2021-0276 primarily affects Juniper Steel-belted Radius Carrier. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-0276?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-0276 published?

CVE-2021-0276 was published on 2021-07-15 and last updated on 2026-06-17.

CVE-2021-0276

CVE-2021-0276 is a critical-severity vulnerability in Juniper Steel-belted Radius Carrier with a CVSS 3.x base score of 9.8. 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-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 6.8
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Juniper Steel-belted Radius Carrier
Published: 2021-07-15
Last modified: 2026-06-17

Description

A stack-based Buffer Overflow vulnerability in Juniper Networks SBR Carrier with EAP (Extensible Authentication Protocol) authentication configured, allows an attacker sending specific packets causing the radius daemon to crash resulting with a Denial of Service (DoS) or leading to remote code execution (RCE). By continuously sending this specific packets, an attacker can repeatedly crash the radius daemon, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks SBR Carrier: 8.4.1 versions prior to 8.4.1R19; 8.5.0 versions prior to 8.5.0R10; 8.6.0 versions prior to 8.6.0R4.

Frequently asked questions

What is CVE-2021-0276?: A stack-based Buffer Overflow vulnerability in Juniper Networks SBR Carrier with EAP (Extensible Authentication Protocol) authentication configured, allows an attacker sending specific packets causing the radius daemon to crash resulting with a Denial of Service (DoS) or leading to remote code execution (RCE). By continuously sending this specific packets, an attacker can repeatedly crash the radius daemon, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks SBR Carrier: 8.4.1 versions prior to 8.4.1R19; 8.5.0 versions prior to 8.5.0R10; 8.6.0 versions prior to 8.6.0R4.
How severe is CVE-2021-0276?: CVE-2021-0276 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-0276 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-0276?: CVE-2021-0276 primarily affects Juniper Steel-belted Radius Carrier. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-0276?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-0276 published?: CVE-2021-0276 was published on 2021-07-15 and last updated on 2026-06-17.

References

https://kb.juniper.net/JSA11180

Affected products (5)

cpe:2.3:a:juniper:steel-belted_radius_carrier:8.4.1:-:*:*:*:*:*:*
cpe:2.3:a:juniper:steel-belted_radius_carrier:8.4.1:r13:*:*:*:*:*:*
cpe:2.3:a:juniper:steel-belted_radius_carrier:8.5.0:-:*:*:*:*:*:*
cpe:2.3:a:juniper:steel-belted_radius_carrier:8.5.0:r4:*:*:*:*:*:*
cpe:2.3:a:juniper:steel-belted_radius_carrier:8.6.0:*:*:*:*:*:*:*

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