OCTOBER 1, 2026
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Case File

CVE-2021-27905

CRITICAL · CVSS 9.8 EPSS 93.05%

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-04-13 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.8. It affects Apache. Its EPSS score suggests a 93.1% probability of exploitation in the next 30 days.

CVE
CVE-2021-27905
Severity
CRITICAL
CVSS
9.8
EPSS
93.05%
Apache

Original NVD Description

The ReplicationHandler (normally registered at "/replication" under a Solr core) in Apache Solr has a "masterUrl" (also "leaderUrl" alias) parameter that is used to designate another ReplicationHandler on another Solr core to replicate index data into the local core. To prevent a SSRF vulnerability, Solr ought to check these parameters against a similar configuration it uses for the "shards" parameter. Prior to this bug getting fixed, it did not. This problem affects essentially all Solr versions prior to it getting fixed in 8.8.2.

Related CVEs

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