CVE-2021-27905

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.

How to fix CVE-2021-27905

To remediate CVE-2021-27905, upgrade the affected package to a fixed version below.

• —upgrade to 8.8.2 or later
• —upgrade to 3.6.2+dfsg-23 or later
• —upgrade to 8.8.2 or later

Is CVE-2021-27905 being exploited?

Likely — EPSS is 93.9%, placing CVE-2021-27905 in the top tier of vulnerabilities by exploitation probability. Prioritise patching.

Affected packages (3)

• from 0, < 8.8.2
• from 0, < 3.6.2+dfsg-23
• from 0, < 8.8.2

CVSS scores

References (25)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-27905
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-27905
• WEBlists.apache.org/thread.html/r0ddc3a82bd7523b1453cb7a5e09eb5559517145425074a42eb326b10%40%3Cannounce.apache.org%3E
• WEBlists.apache.org