Is CVE-2021-32786 in the CISA KEV catalog?

No. CVE-2021-32786 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-32786?

CVE-2021-32786 has a CVSS v3 base score of 4.7 (MEDIUM).

What is the EPSS score for CVE-2021-32786?

CVE-2021-32786 has an EPSS score of 2.36% (82th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-32786?

Upgrade libapache2-mod-auth-openidc on debian 11 to 2.4.9-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-32786

MEDIUMEPSS 82th pctl

4.7

CVSS v3

NVD

Description

mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect with slashes to address a particular breaking change between the different specifications (RFC2396 / RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.

CWE-601Open Redirect

How to fix

Remediation Available

libapache2-mod-auth-openidcDebian

Fixed in:2.4.9-1CVE-2021-32786

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeChanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

2.36%probability of exploitation in 30 days

82ndpercentile

Elevated risk: more likely to be exploited than 82% of all known CVEs.

References

Patch2

Exploit1

daniel.haxx.se

Third-Party Advisory3

Other references3

Related Vulnerabilities

Other CWE-601 (Open Redirect) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-4123	High	7.6	98%	-	Fix
CVE-2018-11784	Medium	4.3	94%	-	Fix
CVE-2021-22881	Medium	6.1	87%	-	Fix
CVE-2022-45402	Medium	6.1	82%	-	Fix
CVE-2017-1000117	High	8.8	78%	-	Fix
CVE-2019-10098	Medium	6.1	74%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.