CVE-2020-11053 json
Open Redirect in OAuth2 Proxy
published 6y ago modified last mo. also BIT-oauth2-proxy-2020-11053 , EUVD-2021-2541 , GHSA-j7px-6hwj-hpjg
- cvss
- 7.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 56%
- public exploits
- 0
- none known
Summary
In OAuth2 Proxy before 5.1.1, there is an open redirect vulnerability. Users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access. This redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites. However, by crafting a redirect URL with HTML encoded whitespace characters the validation could be bypassed and allow a redirect to any URL provided. This has been patched in 5.1.1.
Patch / fix
- go github.com/oauth2-proxy/oauth2-proxy 5.1.1
- bitnami oauth2-proxy 5.1.1
- oauth2_proxy_project oauth2_proxy 5.1.1
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2y ago
Exploit prediction
0.79% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L |
| GitHub | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 5.8 | AV:N/AC:M/Au:N/C:P/I:P/A:N |
| OSV | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/oauth2-proxy/oauth2-proxy | <5.1.1 |
5.1.1 |
| bitnami | oauth2-proxy | <5.1.1 |
5.1.1 |
Affected products
- OAuth2 Proxy OAuth2 Proxy
Classification
- Weakness
-
- CWE-601 URL Redirection to Untrusted Site
References
-
github.com
/oauth2-proxy/oauth2-proxy/commit/0d5fa211df8ef2449347a56b22c779eb8d894c43
web
-
github.com
/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-j7px-6hwj-hpjg
web, vendor-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2020-11053
advisory, web
Sources
- CVE List CVE-2020-11053
- GitHub Advisory GHSA-j7px-6hwj-hpjg
- NVD CVE-2020-11053
- OSV BIT-oauth2-proxy-2020-11053
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.