CVE-2021-21335 json
Basic Authentication can be bypassed using a malformed username
published 2021-03-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8675
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.7%
- EPSS 1.7% chance of exploitation in 30 days, percentile 76%
- public exploits
- 0
- none known
Summary
In the SPNEGO HTTP Authentication Module for nginx (spnego-http-auth-nginx-module) before version 1.1.1 basic Authentication can be bypassed using a malformed username. This affects users of spnego-http-auth-nginx-module that have enabled basic authentication. This is fixed in version 1.1.1 of spnego-http-auth-nginx-module. As a workaround, one may disable basic authentication.
Patch / fix
- spnego_http_authentication_module_project spnego_http_authentication_module 1.1.1
Exploit prediction
1.66% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 7.5 | AV:N/AC:L/Au:N/C:P/I:P/A:P |
Affected products
- stnoonan spnego-http-auth-nginx-module
Classification
- Weakness
-
- CWE-287 Improper Authentication
References
-
github.com
/stnoonan/spnego-http-auth-nginx-module/commit/a06f9efca373e25328b1c53639a48decd0854570
patch, third-party-advisory
-
github.com
/stnoonan/spnego-http-auth-nginx-module/security/advisories/GHSA-ww8q-72rx-hc54
patch, third-party-advisory
-
github.com
/stnoonan/spnego-http-auth-nginx-module/releases/tag/v1.1.1
third-party-advisory
Sources
- CVE List CVE-2021-21335
- NVD CVE-2021-21335
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