How severe is CVE-2020-10534?

CVE-2020-10534 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-10534 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-10534?

CVE-2020-10534 affects Mediawiki. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-10534?

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

When was CVE-2020-10534 published?

CVE-2020-10534 was published on 2020-03-12 and last updated on 2026-06-17.

CVE-2020-10534

CVE-2020-10534 is a critical-severity vulnerability in Mediawiki with a CVSS 3.x base score of 9.8. 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-863.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Mediawiki
Published: 2020-03-12
Last modified: 2026-06-17

Description

In the GlobalBlocking extension before 2020-03-10 for MediaWiki through 1.34.0, an issue related to IP range evaluation resulted in blocked users re-gaining escalated privileges. This is related to the case in which an IP address is contained in two ranges, one of which is locally disabled.

Frequently asked questions

What is CVE-2020-10534?: In the GlobalBlocking extension before 2020-03-10 for MediaWiki through 1.34.0, an issue related to IP range evaluation resulted in blocked users re-gaining escalated privileges. This is related to the case in which an IP address is contained in two ranges, one of which is locally disabled.
How severe is CVE-2020-10534?: CVE-2020-10534 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-10534 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-10534?: CVE-2020-10534 affects Mediawiki. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-10534?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-10534 published?: CVE-2020-10534 was published on 2020-03-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*

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