CVE-2020-1955

CouchDB version 3.0.0 shipped with a new configuration setting that governs access control to the entire database server called `require_valid_user_except_for_up`. It was meant as an extension to the long standing setting `require_valid_user`, which in turn requires that any and all requests to CouchDB will have to be made with valid credentials, effectively forbidding any anonymous requests. The new `require_valid_user_except_for_up` is an off-by-default setting that was meant to allow requiring valid credentials for all endpoints except for the `/_up` endpoint. However, the implementation of this made an error that lead to not enforcing credentials on any endpoint, when enabled. CouchDB versions 3.0.1[1] and 3.1.0[2] fix this issue.

Published: 2020-05-20 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-1955 is rated High Risk (65.9/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.85%). High exploitation likelihood—assess exposure and prioritize 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-2020-1955

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 1.87% 1.85% -0.02%
2 2025-12-28 2.10% 1.87% -0.23%
3 2025-12-27 — 2.10% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-1955

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H 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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P 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:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2020-1955

OS Trackers for CVE-2020-1955

vendor priority summary link
ubuntu medium CVE-2020-1955 medium priority: Ubuntu including 1 source packages (couchdb), 10 status rows across 10 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): DNE 8, needs-triage 1, not-affected 1. https://ubuntu.com/security/CVE-2020-1955

Affected software / configurations for CVE-2020-1955

Vendor Product Version Raw CPE
apache couchdb 3.0.0 cpe:2.3:a:apache:couchdb:3.0.0:*:*:*:*:*:*:*

References for CVE-2020-1955

URL Tags
https://docs.couchdb.org/en/master/cve/2020-1955.html Mitigation Vendor Advisory
cvelogic Threat Intelligence