How severe is CVE-2021-29943?

CVE-2021-29943 has a CVSS 3.x base score of 9.1, 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 none.

Is CVE-2021-29943 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-29943?

CVE-2021-29943 affects Apache Solr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-29943?

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-2021-29943 published?

CVE-2021-29943 was published on 2021-04-13 and last updated on 2026-06-17.

CVE-2021-29943

CVE-2021-29943 is a critical-severity vulnerability in Apache Solr with a CVSS 3.x base score of 9.1. 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 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 5% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Apache Solr
Published: 2021-04-13
Last modified: 2026-06-17

Description

When using ConfigurableInternodeAuthHadoopPlugin for authentication, Apache Solr versions prior to 8.8.2 would forward/proxy distributed requests using server credentials instead of original client credentials. This would result in incorrect authorization resolution on the receiving hosts.

Frequently asked questions

What is CVE-2021-29943?: When using ConfigurableInternodeAuthHadoopPlugin for authentication, Apache Solr versions prior to 8.8.2 would forward/proxy distributed requests using server credentials instead of original client credentials. This would result in incorrect authorization resolution on the receiving hosts.
How severe is CVE-2021-29943?: CVE-2021-29943 has a CVSS 3.x base score of 9.1, 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 none.
Is CVE-2021-29943 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-29943?: CVE-2021-29943 affects Apache Solr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-29943?: 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-2021-29943 published?: CVE-2021-29943 was published on 2021-04-13 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:solr:*:*:*:*:*:*:*:*

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