CVE-2021-27905
SSRF vulnerability with the Replication handler
- Published
- Apr 13, 2021
- Updated
- Aug 3, 2024
- Assigning CNA
- apache
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HHigh · next 30 days
- Percentile
- 99.8%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
5[CVE-2021-27905] Apache Solr ReplicationHandler Server Side Request Forgery (SSRF)
Apache Solr < 8.8.2 Server Side Request Forgery
- Solr-SSRFExploit
Apache Solr SSRF(CVE-2021-27905)
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