Proxmox Virtual Environment (PVE) and Proxmox Mail Gateway (PMG) are vulnerable to SSRF when proxying HTTP requests between pve(pmg)proxy and pve(pmg)daemon. An attacker with an unprivileged account can craft an HTTP request to achieve SSRF and file disclosure of any files on the server. Also, in Proxmox Mail Gateway, privilege escalation to the root@pam account is possible if the backup feature has ever been used, because backup files such as pmg-backup_YYYY_MM_DD_*.tgz have 0644 permissions and contain an authkey value. This is fixed in pve-http-server 4.1-3.
git.proxmox.com/?p=pve-http-server.git%3Ba=commitdiff%3Bh=580d540ea907ba15f64379c5bb69ecf1a49a875f
git.proxmox.com/?p=pve-http-server.git%3Ba=commitdiff%3Bh=c2bd69c7b5e9c775f96021cf8ae53da3dbd9029d
git.proxmox.com/?p=pve-http-server.git%3Ba=commitdiff%3Bh=e9df8a6e76b2a18f89295a5d92a62177bbf0f762
starlabs.sg/blog/2022/12-multiple-vulnerabilites-in-proxmox-ve--proxmox-mail-gateway/