CVE-2021-35656Network attack vector

Unauthenticated service interruption via undisclosed filter flaw

Published Oct 20, 2021 · Updated Sep 25, 2024

Denial of service in Oracle Outside In Technology 8.5.5 allows remote attackers to hang or repeatedly crash the service over HTTP. Oracle identifies the affected locus as Outside In Filters but has not published the malformed input or incorrect filter operation that triggers the failure. Exposure requires a consuming application to pass network-received data directly to the SDK; successful attacks affect availability only.

CVSS severity7.5
High
EPSS probability1.47%
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 Oracle Outside In Technology 8.5.5 allows remote attackers to hang or repeatedly crash the service over HTTP. Oracle identifies the affected locus as Outside In Filters but has not published the malformed input or incorrect filter operation that triggers the failure. Exposure requires a consuming application to pass network-received data directly to the SDK; successful attacks affect availability only.

The record

CVE
CVE-2021-35656
Published
Oct 20, 2021
Updated
Sep 25, 2024
Vendor
Oracle Corporation
Product
Oracle Outside In Technology
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 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

5.0NISTAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5Oracle CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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