How severe is CVE-2021-2420?

CVE-2021-2420 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-2420 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-2420?

CVE-2021-2420 affects Oracle Outside In Technology. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-2420?

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

When was CVE-2021-2420 published?

CVE-2021-2420 was published on 2021-07-21 and last updated on 2026-06-17.

CVE-2021-2420

CVE-2021-2420 is a high-severity vulnerability in Oracle Outside In Technology with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Oracle Outside In Technology
Published: 2021-07-21
Last modified: 2026-06-17

Description

Vulnerability in the Oracle Outside In Technology product of Oracle Fusion Middleware (component: Outside In Filters). The supported version that is affected is 8.5.5. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Oracle Outside In Technology. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle Outside In Technology. Note: Outside In Technology is a suite of software development kits (SDKs). The protocol and CVSS Base Score depend on the software that uses Outside In Technology. The CVSS score assumes that the software passes data received over a network directly to Outside In Technology, but if data is not received over a network the CVSS score may be lower. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Frequently asked questions

What is CVE-2021-2420?: Vulnerability in the Oracle Outside In Technology product of Oracle Fusion Middleware (component: Outside In Filters). The supported version that is affected is 8.5.5. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Oracle Outside In Technology. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle Outside In Technology. Note: Outside In Technology is a suite of software development kits (SDKs). The protocol and CVSS Base Score depend on the software that uses Outside In Technology. The CVSS score assumes that the software passes data received over a network directly to Outside In Technology, but if data is not received over a network the CVSS score may be lower. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
How severe is CVE-2021-2420?: CVE-2021-2420 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-2420 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-2420?: CVE-2021-2420 affects Oracle Outside In Technology. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-2420?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-2420 published?: CVE-2021-2420 was published on 2021-07-21 and last updated on 2026-06-17.

References

https://www.oracle.com/security-alerts/cpujul2021.html

Affected products (1)

cpe:2.3:a:oracle:outside_in_technology:8.5.5:*:*:*:*:*:*:*

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