CVE-2021-26558Network attack vector

External link injection via unsafe deserialization

Published Nov 11, 2021 · Updated Aug 3, 2024

Deserialization of untrusted data in Apache ShardingSphere-UI 4.1.1 through 4.x allows remote attackers to inject external link resources. The vendor has not disclosed the affected endpoint, serialized format, deserialization routine, or missing validation that permits the injection. The interface is network-reachable without prior authentication, and successful exploitation changes application-managed link data without reported disclosure or service interruption.

CVSS severity7.5
High
EPSS probability2.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization of untrusted data in Apache ShardingSphere-UI 4.1.1 through 4.x allows remote attackers to inject external link resources. The vendor has not disclosed the affected endpoint, serialized format, deserialization routine, or missing validation that permits the injection. The interface is network-reachable without prior authentication, and successful exploitation changes application-managed link data without reported disclosure or service interruption.

The record

CVE
CVE-2021-26558
Published
Nov 11, 2021
Updated
Aug 3, 2024
Vendor
The Apache Software Foundation
Product
Apache ShardingSphere-UI
Classifications
CWE-502, CAPEC-586
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=4.1.1 <Apache ShardingSphere-UI* changes=[{"at":"5.0.0","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache ShardingSphere-UIversion=4.1.1 <Apache ShardingSphere-UI* changes=[{"at":"5.0.0","status":"unaffected"}]

Published CVSS scores

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

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

CWE-502Deserialization of Untrusted Data
CAPEC-586Object Injection

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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