GHSA-4v48-4q5m-8vx4
Prometheus vulnerable to basic authentication bypass
Impact
Prometheus can be secured by a web.yml file that specifies usernames and hashed passwords for basic authentication.
Passwords are hashed with bcrypt, which means that even if you have access to the hash, it is very hard to find the original password back.
However, a flaw in the way this mechanism was implemented in the exporter toolkit makes it possible with people who know the hashed password to authenticate against Prometheus.
A request can be forged by an attacker to poison the internal cache used to cache the computation of hashes and make subsequent requests successful. This cache is used in both happy and unhappy scenarios in order to limit side channel attacks that could tell an attacker if a user is present in the file or not.
Patches
Prometheus 2.37.4 (LTS) and 2.40.4 have been released to address this issue.
Workarounds
There is no workaround but attacker must have access to the hashed password, stored in disk, to bypass the authentication.
Credit
We want to thank Lei Wan for reporting this security issue.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
What each source reports
GitHub Advisories Score used
Prometheus vulnerable to basic authentication bypass
Impact
Prometheus can be secured by a web.yml file that specifies usernames and hashed passwords for basic authentication.
Passwords are hashed with bcrypt, which means that even if you have access to the hash, it is very hard to find the original password back.
However, a flaw in the way this mechanism was implemented in the exporter toolkit makes it possible with people who know the hashed password to authenticate against Prometheus.
A request can be forged by an attacker to poison the internal cache used to cache the computation of hashes and make subsequent requests successful. This cache is used in both happy and unhappy scenarios in order to limit side channel attacks that could tell an attacker if a user is present in the file or not.
Patches
Prometheus 2.37.4 (LTS) and 2.40.4 have been released to address this issue.
Workarounds
There is no workaround but attacker must have access to the hashed password, stored in disk, to bypass the authentication.
Credit
We want to thank Lei Wan for reporting this security issue.
- Record
GHSA-4v48-4q5m-8vx4- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-303
- Updated
- 2026-11-02
OSV
Prometheus vulnerable to basic authentication bypass
Impact
Prometheus can be secured by a web.yml file that specifies usernames and hashed passwords for basic authentication.
Passwords are hashed with bcrypt, which means that even if you have access to the hash, it is very hard to find the original password back.
However, a flaw in the way this mechanism was implemented in the exporter toolkit makes it possible with people who know the hashed password to authenticate against Prometheus.
A request can be forged by an attacker to poison the internal cache used to cache the computation of hashes and make subsequent requests successful. This cache is used in both happy and unhappy scenarios in order to limit side channel attacks that could tell an attacker if a user is present in the file or not.
Patches
Prometheus 2.37.4 (LTS) and 2.40.4 have been released to address this issue.
Workarounds
There is no workaround but attacker must have access to the hashed password, stored in disk, to bypass the authentication.
Credit
We want to thank Lei Wan for reporting this security issue.
- Record
GHSA-4v48-4q5m-8vx4- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-303
- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/prometheus/prometheusGo | 2.24.1 up to 2.37.4 | 2.37.4 |
github.com/prometheus/prometheusGo | 2.38.0 up to 2.40.4 | 2.40.4 |
github.com/prometheus/prometheus/v2Go | 2.24.1 up to 2.37.4 | 2.37.4 |
github.com/prometheus/prometheus/v2Go | 2.38.0 up to 2.40.4 | 2.40.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
GHSA-4v48-4q5m-8vx4 is a high vulnerability (CVSS 7.2) in github.com/prometheus/prometheus, published December 5, 2022. No source lists public exploit code. Fixed in github.com/prometheus/prometheus 2.37.4.