CVE-2026-67990
basecamp/upright at commit efe4f2e5254ac6e57e45d2261804cca74dbbca3f disables Rails CSRF protection for its Alertmanager and Prometheus proxy controllers.
Does this matter?
Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own.
Description
basecamp/upright at commit efe4f2e5254ac6e57e45d2261804cca74dbbca3f disables Rails CSRF protection for its Alertmanager and Prometheus proxy controllers. An unauthenticated attacker can induce a logged-in user's browser to submit requests that are forwarded to enabled upstream write or management endpoints, such as creating an Alertmanager silence or requesting a Prometheus reload. The final impact depends on the APIs enabled by the upstream services.
- CVSS 3.1
- 5.4 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- EPSS
- 0.18% probability · 8th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-352
- Source
- cve@mitre.org
EPSS 0.2% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://gist.github.com/Zykis1024/cec690012eecac53f408e78d2b569f06
- https://github.com/basecamp/upright
- https://github.com/basecamp/upright/blob/efe4f2e5254ac6e57e45d2261804cca74dbbca3f/app/controllers/upright/alertmanager_proxy_controller.rb#L2
- https://github.com/basecamp/upright/blob/efe4f2e5254ac6e57e45d2261804cca74dbbca3f/app/controllers/upright/prometheus_proxy_controller.rb#L2
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.