CVE & CISA-KEV Catalog

CVE-2021-32637

CRITICALEPSS 77th pctl
10.0
CVSS v3
NVD

Description

Authelia is a a single sign-on multi-factor portal for web apps. This affects uses who are using nginx ngx_http_auth_request_module with Authelia, it allows a malicious individual who crafts a malformed HTTP request to bypass the authentication mechanism. It additionally could theoretically affect other proxy servers, but all of the ones we officially support except nginx do not allow malformed URI paths. The problem is rectified entirely in v4.29.3. As this patch is relatively straightforward we can back port this to any version upon request. Alternatively we are supplying a git patch to 4.25.1 which should be relatively straightforward to apply to any version, the git patches for specific versions can be found in the references. The most relevant workaround is upgrading. You can also add a block which fails requests that contains a malformed URI in the internal location block.

How to fix

Remediation Available
autheliaNVD
Affected:>= 4.26.0, < 4.29.3Fixed in:4.29.3CVE-2021-32637derived from NVD

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 InteractionNone
ScopeChanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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

Exploit Intelligence

1.87%probability of exploitation in 30 days
77thpercentile

Elevated risk: more likely to be exploited than 77% of all known CVEs.

References

Related Vulnerabilities

Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-35082Critical9.8100%KEV + RansomFix
CVE-2023-35078Critical9.8100%KEV + RansomFix
CVE-2017-7921Critical9.8100%KEV-
CVE-2024-7593Critical9.8100%KEV-
CVE-2023-46805High8.2100%KEV + Ransom-
CVE-2022-40684Critical9.8100%KEV + RansomFix
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Markdown

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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.