SSRF in Apache Solr
CVE-2021-27905
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.931 (99.8th percentile), scored .
High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.931 · newest: 0.931 · change: 0.000
Affected products
- Apache Solr
- Apache Software Foundation Solr — versions Apache Solr
Weakness classification (CWE)
Public proof-of-concept exploits
References
- lists.apache.org/thread.html/r0ddc3a82bd7523b1453cb7a5e09eb5559517145425074a42e… (Mailing List, Vendor Advisory)
- security.netapp.com/advisory/ntap-20210611-0009/ (Third Party Advisory)
- lists.apache.org/thread.html/r95df34bb158375948da82b4dfe9a1b5d528572d586584162f… (mailing-list)
- lists.apache.org/thread.html/r140128dc6bb4f4e0b6a39e962c7ca25a8cbc8e48ed766176c… (mailing-list)
- lists.apache.org/thread.html/r3da74965aba2b5f5744b7289ad447306eeb2940c872801819… (mailing-list)
- lists.apache.org/thread.html/rae9ccaecce9859f709ed1458545d90a4c07163070dc98b5e9… (mailing-list)
- lists.apache.org/thread.html/r720a4a0497fc90bad5feec8aa18b777912ee15c7eeb5f882a… (mailing-list)
- lists.apache.org/thread.html/re9d64bb8e5dfefddcbf255adb4559e13a0df5b818da1b9b51… (mailing-list)
- lists.apache.org/thread.html/rd232d77c57a8ce172359ab098df9512d8b37373ab87c444be… (mailing-list)
- lists.apache.org/thread.html/r78a3a4f1138a1608b0c6d4a2ee7647848c1a20b0d5c652cd9… (mailing-list)
Frequently asked questions
- What is CVE-2021-27905?
- CVE-2021-27905 is a critical-severity vulnerability in Apache Solr, classified under Server-Side Request Forgery (SSRF). CVSS score: 9.8/10. Published 2021-04-13.
- How severe is CVE-2021-27905?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2021-27905 known to be exploited?
- 40 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.