CVE-2021-2451Network attack vector

Unauthenticated denial of service

Published Jul 20, 2021 · Updated Sep 25, 2024

Denial of service in Outside In Filters in Oracle Outside In Technology 8.5.5 allows remote attackers to cause crashes via HTTP. The vendor has not disclosed the specific parser operation or code locus that mishandles untrusted input. Exploitation requires a consuming application to pass attacker-controlled network data directly to the SDK; successful attacks hang or repeatedly crash that application, interrupting availability without reported confidentiality or integrity impact.

CVSS severity7.5
High
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Outside In Filters in Oracle Outside In Technology 8.5.5 allows remote attackers to cause crashes via HTTP. The vendor has not disclosed the specific parser operation or code locus that mishandles untrusted input. Exploitation requires a consuming application to pass attacker-controlled network data directly to the SDK; successful attacks hang or repeatedly crash that application, interrupting availability without reported confidentiality or integrity impact.

The record

CVE
CVE-2021-2451
Published
Jul 20, 2021
Updated
Sep 25, 2024
Vendor
Oracle Corporation
Product
Oracle Outside In Technology
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.5.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · Oracle Outside In Technologyversion=8.5.5

Published CVSS scores

7.5OracleCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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