CVE-2021-27905

SSRF vulnerability with the Replication handler

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.

Remediation

Workaround:

  • Ensure that any access to the replication handler is purely internal to Solr. Typically, it's only accessed externally for diagnostic/informational purposes.

Category

9.8
CVSS
Severity: Critical
CVSS 3.1 •
CVSS 2.0 •
EPSS 94.19% Top 5%
Vendor Advisory apache.org
Affected: Apache Software Foundation Apache Solr
Published at:
Updated at:

References

Link Tags
https://lists.apache.org/thread.html/r0ddc3a82bd7523b1453cb7a5e09eb5559517145425074a42eb326b10%40%3Cannounce.apache.org%3E mailing list vendor advisory
https://security.netapp.com/advisory/ntap-20210611-0009/ third party advisory
https://lists.apache.org/thread.html/r95df34bb158375948da82b4dfe9a1b5d528572d586584162f8f5aeef%40%3Cusers.solr.apache.org%3E mailing list
https://lists.apache.org/thread.html/r140128dc6bb4f4e0b6a39e962c7ca25a8cbc8e48ed766176c931fccc%40%3Cusers.solr.apache.org%3E mailing list
https://lists.apache.org/thread.html/r3da74965aba2b5f5744b7289ad447306eeb2940c872801819faa9314%40%3Cusers.solr.apache.org%3E mailing list
https://lists.apache.org/thread.html/rae9ccaecce9859f709ed1458545d90a4c07163070dc98b5e9e59057f%40%3Cnotifications.ofbiz.apache.org%3E mailing list
https://lists.apache.org/thread.html/r720a4a0497fc90bad5feec8aa18b777912ee15c7eeb5f882adbf523e%40%3Ccommits.ofbiz.apache.org%3E mailing list
https://lists.apache.org/thread.html/re9d64bb8e5dfefddcbf255adb4559e13a0df5b818da1b9b51329723f%40%3Cnotifications.ofbiz.apache.org%3E mailing list
https://lists.apache.org/thread.html/rd232d77c57a8ce172359ab098df9512d8b37373ab87c444be911b430%40%3Cnotifications.ofbiz.apache.org%3E mailing list
https://lists.apache.org/thread.html/r78a3a4f1138a1608b0c6d4a2ee7647848c1a20b0d5c652cd9b02c25a%40%3Ccommits.ofbiz.apache.org%3E mailing list
https://lists.apache.org/thread.html/r6ccec7fc54d82591b23c143f1f6a6e38f6e03e75db70870e4cb14a1a%40%3Ccommits.ofbiz.apache.org%3E mailing list
https://lists.apache.org/thread.html/r8f1152a43c36d878bbeb5a92f261e9efaf3af313b033d7acfccea59d%40%3Cnotifications.ofbiz.apache.org%3E mailing list

Frequently Asked Questions

What is the severity of CVE-2021-27905?
CVE-2021-27905 has been scored as a critical severity vulnerability.
How to fix CVE-2021-27905?
As a workaround for remediating CVE-2021-27905: Ensure that any access to the replication handler is purely internal to Solr. Typically, it's only accessed externally for diagnostic/informational purposes.
Is CVE-2021-27905 being actively exploited in the wild?
It is possible that CVE-2021-27905 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~94% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-27905?
CVE-2021-27905 affects Apache Software Foundation Apache Solr.
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