How severe is CVE-2021-26558?

CVE-2021-26558 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 high, and availability none.

Is CVE-2021-26558 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26558?

CVE-2021-26558 affects Apache Shardingsphere-ui. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26558?

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-2021-26558 published?

CVE-2021-26558 was published on 2021-11-11 and last updated on 2026-06-17.

CVE-2021-26558

CVE-2021-26558 is a high-severity vulnerability in Apache Shardingsphere-ui 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. The underlying weakness is classified as CWE-502.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Apache Shardingsphere-ui
Published: 2021-11-11
Last modified: 2026-06-17

Description

Deserialization of Untrusted Data vulnerability of Apache ShardingSphere-UI allows an attacker to inject outer link resources. This issue affects Apache ShardingSphere-UI Apache ShardingSphere-UI version 4.1.1 and later versions; Apache ShardingSphere-UI versions prior to 5.0.0.

Frequently asked questions

What is CVE-2021-26558?: Deserialization of Untrusted Data vulnerability of Apache ShardingSphere-UI allows an attacker to inject outer link resources. This issue affects Apache ShardingSphere-UI Apache ShardingSphere-UI version 4.1.1 and later versions; Apache ShardingSphere-UI versions prior to 5.0.0.
How severe is CVE-2021-26558?: CVE-2021-26558 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 high, and availability none.
Is CVE-2021-26558 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26558?: CVE-2021-26558 affects Apache Shardingsphere-ui. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26558?: 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-2021-26558 published?: CVE-2021-26558 was published on 2021-11-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:shardingsphere-ui:*:*:*:*:*:*:*:*

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