Prometheus Blackbox Exporter through 0.17.0 allows /probe?target= SSRF. NOTE: follow-on discussion suggests that this might plausibly be interpreted as both intended functionality and also a vulnerability
https://www.openwall.com/lists/oss-security/2020/08/08/3
https://www.openwall.com/lists/oss-security/2020/08/08/12