What is the CVSS score of CVE-2021-27905?

CVE-2021-27905 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 93.1%.

Is there a public PoC exploit available for CVE-2021-27905?

Yes, a public proof-of-concept exploit is available for CVE-2021-27905. Prioritise patching immediately. EPSS: 93.1%.

Is there a patch available for CVE-2021-27905?

Yes, a patch is available for CVE-2021-27905. Update the affected software to the latest version immediately.

Solr CVE-2021-27905

CRITICAL

Server-Side Request Forgery (SSRF) (CWE-918)

2021-04-13 security@apache.org

Apache SSRF Solr

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Apr 13, 2021 - 07:15 nvd

CRITICAL 9.8

DescriptionNVD

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.

AnalysisAI

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. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Server-Side Request Forgery (SSRF) (CWE-918), which allows attackers to make the server perform requests to unintended internal or external resources. 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. Affected products include: Apache Solr.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate and allowlist destination URLs, block requests to internal networks, use network segmentation.