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CVE-2023-36456

Authentik lacks Proxy IP headers validation

8.3 HighFix available

authentik is an open-source Identity Provider. Prior to versions 2023.4.3 and 2023.5.5, authentik does not verify the source of the X-Forwarded-For and X-Real-IP headers, both in the Python code and the go code. Only authentik setups that are directly accessible by users without a reverse proxy are susceptible to this. Possible spoofing of IP addresses in logs, downstream applications proxied by (built in) outpost, IP bypassing in custom flows if used.

This poses a possible security risk when someone has flows or policies that check the user's IP address, e.g. when they want to ignore the user's 2 factor authentication when the user is connected to the company network. A second security risk is that the IP addresses in the logfiles and user sessions are not reliable anymore. Anybody can spoof this address and one cannot verify that the user has logged in from the IP address that is in their account's log. A third risk is that this header is passed on to the proxied application behind an outpost. The application may do any kind of verification, logging, blocking or rate limiting based on the IP address, and this IP address can be overridden by anybody that want to.

Versions 2023.4.3 and 2023.5.5 contain a patch for this issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
Low

Exploit likelihood

0.79%Up 0.7 points since Jul 7, 2023
90%50%10%1%

What each source reports

CVE List Score used 8.3

Authentik lacks Proxy IP headers validation

authentik is an open-source Identity Provider. Prior to versions 2023.4.3 and 2023.5.5, authentik does not verify the source of the X-Forwarded-For and X-Real-IP headers, both in the Python code and the go code. Only authentik setups that are directly accessible by users without a reverse proxy are susceptible to this. Possible spoofing of IP addresses in logs, downstream applications proxied by (built in) outpost, IP bypassing in custom flows if used.

This poses a possible security risk when someone has flows or policies that check the user's IP address, e.g. when they want to ignore the user's 2 factor authentication when the user is connected to the company network. A second security risk is that the IP addresses in the logfiles and user sessions are not reliable anymore. Anybody can spoof this address and one cannot verify that the user has logged in from the IP address that is in their account's log. A third risk is that this header is passed on to the proxied application behind an outpost. The application may do any kind of verification, logging, blocking or rate limiting based on the IP address, and this IP address can be overridden by anybody that want to.

Versions 2023.4.3 and 2023.5.5 contain a patch for this issue.

Record
CVE-2023-36456
CVSS 3.1
8.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Weakness
CWE-436
Updated
2026-11-02
EUVDEUVD-2023-40420 8.3

authentik is an open-source Identity Provider. Prior to versions 2023.4.3 and 2023.5.5, authentik does not verify the source of the X-Forwarded-For and X-Real-IP headers, both in the Python code and the go code. Only authentik setups that are directly accessible by users without a reverse proxy are susceptible to this. Possible spoofing of IP addresses in logs, downstream applications proxied by (built in) outpost, IP bypassing in custom flows if used.

This poses a possible security risk when someone has flows or policies that check the user's IP address, e.g. when they want to ignore the user's 2 factor authentication when the user is connected to the company network. A second security risk is that the IP addresses in the logfiles and user sessions are not reliable anymore. Anybody can spoof this address and one cannot verify that the user has logged in from the IP address that is in their account's log. A third risk is that this header is passed on to the proxied application behind an outpost. The application may do any kind of verification, logging, blocking or rate limiting based on the IP address, and this IP address can be overridden by anybody that want to.

Versions 2023.4.3 and 2023.5.5 contain a patch for this issue.

Record
EUVD-2023-40420
CVSS 3.1
8.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Updated
2026-11-03
NVD 8.3

authentik is an open-source Identity Provider. Prior to versions 2023.4.3 and 2023.5.5, authentik does not verify the source of the X-Forwarded-For and X-Real-IP headers, both in the Python code and the go code. Only authentik setups that are directly accessible by users without a reverse proxy are susceptible to this. Possible spoofing of IP addresses in logs, downstream applications proxied by (built in) outpost, IP bypassing in custom flows if used.

This poses a possible security risk when someone has flows or policies that check the user's IP address, e.g. when they want to ignore the user's 2 factor authentication when the user is connected to the company network. A second security risk is that the IP addresses in the logfiles and user sessions are not reliable anymore. Anybody can spoof this address and one cannot verify that the user has logged in from the IP address that is in their account's log. A third risk is that this header is passed on to the proxied application behind an outpost. The application may do any kind of verification, logging, blocking or rate limiting based on the IP address, and this IP address can be overridden by anybody that want to.

Versions 2023.4.3 and 2023.5.5 contain a patch for this issue.

Record
CVE-2023-36456
CVSS 3.1
8.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness
CWE-436
Updated
2026-11-02
OSV 8.3

Authentik lacks Proxy IP headers validation

authentik is an open-source Identity Provider. Prior to versions 2023.4.3 and 2023.5.5, authentik does not verify the source of the X-Forwarded-For and X-Real-IP headers, both in the Python code and the go code. Only authentik setups that are directly accessible by users without a reverse proxy are susceptible to this. Possible spoofing of IP addresses in logs, downstream applications proxied by (built in) outpost, IP bypassing in custom flows if used.

This poses a possible security risk when someone has flows or policies that check the user's IP address, e.g. when they want to ignore the user's 2 factor authentication when the user is connected to the company network. A second security risk is that the IP addresses in the logfiles and user sessions are not reliable anymore. Anybody can spoof this address and one cannot verify that the user has logged in from the IP address that is in their account's log. A third risk is that this header is passed on to the proxied application behind an outpost. The application may do any kind of verification, logging, blocking or rate limiting based on the IP address, and this IP address can be overridden by anybody that want to.

Versions 2023.4.3 and 2023.5.5 contain a patch for this issue.

Record
CVE-2023-36456
CVSS 3.1
8.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Weakness
CWE-436
Updated
2026-11-02
OSVBIT-authentik-2023-36456 No score

Authentik lacks Proxy IP headers validation

authentik is an open-source Identity Provider. Prior to versions 2023.4.3 and 2023.5.5, authentik does not verify the source of the X-Forwarded-For and X-Real-IP headers, both in the Python code and the go code. Only authentik setups that are directly accessible by users without a reverse proxy are susceptible to this. Possible spoofing of IP addresses in logs, downstream applications proxied by (built in) outpost, IP bypassing in custom flows if used.

This poses a possible security risk when someone has flows or policies that check the user's IP address, e.g. when they want to ignore the user's 2 factor authentication when the user is connected to the company network. A second security risk is that the IP addresses in the logfiles and user sessions are not reliable anymore. Anybody can spoof this address and one cannot verify that the user has logged in from the IP address that is in their account's log. A third risk is that this header is passed on to the proxied application behind an outpost. The application may do any kind of verification, logging, blocking or rate limiting based on the IP address, and this IP address can be overridden by anybody that want to.

Versions 2023.4.3 and 2023.5.5 contain a patch for this issue.

Record
BIT-authentik-2023-36456
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
authentik
Bitnami
before 2023.4.3, 2023.5.0 up to 2023.5.5
2023.4.32023.5.5

History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-36456 is a high vulnerability (CVSS 8.3) in Goauthentik Authentik, published July 6, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.79%, the 56th percentile. Fixed in authentik 2023.4.3.

References

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