CVE-2020-17516

Apache Cassandra versions 2.1.0 to 2.1.22, 2.2.0 to 2.2.19, 3.0.0 to 3.0.23, and 3.11.0 to 3.11.9, when using 'dc' or 'rack' internode_encryption setting, allows both encrypted and unencrypted internode connections. A misconfigured node or a malicious user can use the unencrypted connection despite not being in the same rack or dc, and bypass mutual TLS requirement.

Published: 2021-02-03 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-17516 is rated Moderate Risk (58.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.93%). EPSS rose +1.08% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-17516

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.85% 1.93% +1.08%
2 2025-12-06 0.38% 0.85% +0.47%
3 2025-11-21 — 0.38% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-17516

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-17516

GitHub Security Advisory for CVE-2020-17516

GHSA-2vxm-vp4c-fjfw · Severity: high · Ecosystem: maven — Authentication Bypass in Apache Cassandra

OS Trackers for CVE-2020-17516

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2020-17516
suse medium CVE-2020-17516 severity moderate: SUSE including 131 source package names (ardana-cobbler-8.0+git.1614096566.e8c2b27-3.44.3, ardana-neutron-9.0+git.1615223676.777f0b3-3.25.2, …), 250 product×package rows across 5 product lines (HPE Helion OpenStack 8, SUSE OpenStack Cloud 8, … (5 product lines)): Fixed 250. https://www.suse.com/security/cve/CVE-2020-17516/

Affected software / configurations for CVE-2020-17516

Vendor Product Version Raw CPE
apache cassandra >= 2.1.0, <= 2.1.22 cpe:2.3:a:apache:cassandra:*:*:*:*:*:*:*:*
apache cassandra >= 2.2.0, <= 2.2.19 cpe:2.3:a:apache:cassandra:*:*:*:*:*:*:*:*
apache cassandra >= 3.0.0, <= 3.0.23 cpe:2.3:a:apache:cassandra:*:*:*:*:*:*:*:*
apache cassandra >= 3.11.0, <= 3.11.9 cpe:2.3:a:apache:cassandra:*:*:*:*:*:*:*:*

References for CVE-2020-17516

cvelogic Threat Intelligence