CVE-2021-27905: apache software foundation apache solr Server-Side Request Forgery (SSRF)
Vulnerability summary
CVE-2021-27905 is a critical (CVSS 9.8) Server-Side Request Forgery (SSRF) vulnerability in apache software foundation apache solr. EPSS estimates a 93.05% chance of exploitation in the next 30 days, higher than 99.8% of scored vulnerabilities.
Timeline
- 13-04-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · MavenEcosystem advisory · calculated7.1HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:NDiffers
EPSS trend
Probability
93.05%
Chance of exploitation in the next 30 days
Percentile
100%
Versus all other CVEs
30-day change
0.00 pp
From 93.05% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Apache1 product
- solr< 8.8.2
Apache software foundation1 product
- apache solr≥ Apache Solr, < 8.8.2
Debian1 product
- lucene-solr< 3.6.2+dfsg-23
Org.apache.solr1 product
- solr-parent< 8.8.2
Ubuntu1 product
- lucene-solrAll versions (No fix recorded)
5 vendors · 5 products
