CVE-2021-27905

highpriority · act · 82EPSS 0.931 · 100 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

5 exploits · PoC

Likely / severe?

93.1% (100th) EPSS

CVSS 7.5 · high

Is it mine?

4 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-27

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

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.1–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.17.1highCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:Nsecondary · OSV

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-918USprimaryCWE-918US

exploits (5)

Public proof-of-concept and weaponised exploit code.

Henry4E36/Solr-SSRFApache Solr SSRF(CVE-2021-27905)PoC · poc_in_github
RIZZZIOM/CVE-2021-27905Apache Solr < 8.8.2 Server Side Request ForgeryPoC · poc_in_github
W2Ning/Solr-SSRFCVE-2021-27905PoC · poc_in_github
murataydemir/CVE-2021-27905[CVE-2021-27905] Apache Solr ReplicationHandler Server Side Request Forgery (SSRF)PoC · poc_in_github
pdelteil/CVE-2021-27905.POCPOC for LFI related to CVE-2021-27905PoC · poc_in_github

affected products (4)

Products and version ranges known to be affected.

Apache Software Foundation Apache SolrApache Solr → 8.8.2enisa_euvdEU
apache solr< 8.8.2nvdUScpe:2.3:a:apache:solr:*:*:*:*:*:*:*:*
Bitnami solr< 8.8.2osvUSpkg:bitnami/solr
Maven org.apache.solr:solr-parent< 8.8.2osvUSpkg:maven/org.apache.solr/solr-parent

advisories (2)

Vendor and ecosystem advisories describing this.

GHSA-5phw-3jrp-3vj8Server-Side Request Forgery in Apache Solr2021-05-10ghsa · osvUS
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.
BIT-solr-2021-27905SSRF vulnerability with the Replication handler2024-03-06vendor · osvUS
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.

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2021-04-13modified 2026-06-17

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references (40)

External citations — patches, advisories, analysis.

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