CVE-2026-42312

### Summary The `set_config_value()` API method (`@permission(Perms.SETTINGS)`) in `src/pyload/core/api/__init__.py` gates security-sensitive options behind a hand-maintained allowlist `ADMIN_ONLY_CORE_OPTIONS`. The option `("general", "ssl_verify")` is **not** on that allowlist. Any authenticated user with the non-admin `SETTINGS` permission can set `general.ssl_verify = off`, and every subsequent outbound pycurl request is made with `SSL_VERIFYPEER=0` and `SSL_VERIFYHOST=0` — TLS peer and hostname verification are fully disabled. An on-path attacker can then present forged certificates for any hostname pyload fetches. This is a direct continuation of the fix family CVE-2026-33509 / CVE-2026-35463 / CVE-2026-35464 / CVE-2026-35586, each of which patched a different missed option in the same allowlist. ### Details **Writer** — `src/pyload/core/api/__init__.py`, `set_config_value()` (around lines 215–290). The function is decorated with `@permission(Perms.SETTINGS)` and only rejects writes when `(category, option)` appears in `ADMIN_ONLY_CORE_OPTIONS`: ```python ADMIN_ONLY_CORE_OPTIONS = { ("general", "storage_folder"), ("log", "syslog_host"), ("log", "syslog_port"), ("proxy", "password"), ("proxy", "username"), ("reconnect", "script"), ("webui", "host"), ("webui", "ssl_certfile"), ("webui", "ssl_keyfile"), ("webui", "ssl_certchain"), ("webui", "use_ssl"), } ... if (category, option) in ADMIN_ONLY_CORE_OPTIONS and not is_admin: self.pyload.log.error(...); return self.pyload.config.set(category, option, value) ``` `("general", "ssl_verify")` is absent. `config.set()` in `src/pyload/core/config/parser.py:329` calls `cast()` which has no branch for enum-string types — `"off"` is stored verbatim and persisted to disk via `self.save()`. **Reader** — `src/pyload/core/network/request_factory.py:109-110`: ```python def get_options(self): return { "interface": self.iface(), "proxies": self.get_proxies(), "ipv6": self.pyload.config.get("download", "ipv6"), "ssl_verify": self.pyload.config.get("general", "ssl_verify"), ... } ``` **Sink** — `src/pyload/core/network/http/http_request.py:193-206`: ```python if "ssl_verify" in options: aiachaser_on = b"on (using aia-chaser)" if options["ssl_verify"] in [True, b"on", aiachaser_on]: ... ssl_verify = 1 else: ssl_verify = 0 self.c.setopt(pycurl.SSL_VERIFYPEER, ssl_verify) self.c.setopt(pycurl.SSL_VERIFYHOST, ssl_verify * 2) ``` Because `get_options()` is invoked every time a new pycurl handle is built, the new config value takes effect on the very next outbound request — no pyload restart required. ### PoC Authenticated as any user who has `Perms.SETTINGS` but is **not** admin (e.g. a user with `Role.USER` + the SETTINGS permission bit): ```bash # 1) Log in as the SETTINGS (non-admin) user. curl -c cookies.txt -X POST http://pyload.example:8000/api/login \ -d 'username=settings_user&password=<password>' # 2) Disable TLS verification for all outbound downloads. curl -b cookies.txt -X POST http://pyload.example:8000/api/setConfigValue \ -d 'category=general&option=ssl_verify&value=off&section=core' # -> 200 OK. Config persisted. # 3) Enqueue any HTTPS download. An on-path attacker (shared LAN, # compromised upstream router, DNS hijack, or a malicious proxy # enabled via the sibling advisory on the proxy.* options) can # now present a forged cert for any target — pyload accepts it. ``` Verification: observe pycurl `SSL_VERIFYPEER=0` in a debug build, or confirm that a download from an HTTPS endpoint served with a self-signed / mismatched cert succeeds after step 2 and fails before it. ### Impact - **Who**: any authenticated user whose role was granted `Perms.SETTINGS`. In multi-user pyload deployments that delegate settings administration to non-admins, this is an unintended privilege escalation from "can change UI/download settings" to "can silently disable TLS cert validation for all outbound fetches". - **What**: 1. Man-in-the-middle on all HTTPS downloads, captcha fetches, update checks, and plugin HTTP calls. 2. Extends the impact of the already-published SSRF chain (CVE-2026-33992 / CVE-2026-35459). The URL-hostname validation those patches added is only meaningful if the TLS channel authenticates the endpoint; with `ssl_verify=off`, an on-path attacker can present forged certs for already-validated hosts — so HTTPS cloud-metadata endpoints and internal HTTPS services behind the host allowlist become reachable again. 3. Silent to the admin. Every adjacent security-critical option (`proxy.password`, SSL certfile/keyfile/certchain, `use_ssl`) is already admin-only, so the admin's mental model is that TLS policy cannot be weakened by a non-admin. - **Not impacted**: unauthenticated attackers; users holding only `DOWNLOAD` / `LIST` roles.

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev100, the set_config_value() API method (@permission(Perms.SETTINGS)) in src/pyload/core/api/__init__.py gates security-sensitive options behind a hand-maintained allowlist ADMIN_ONLY_CORE_OPTIONS. The option ("general", "ssl_verify") is not on that allowlist. Any authenticated user with the non-admin SETTINGS permission can set general.ssl_verify = off, and every subsequent outbound pycurl request is made with SSL_VERIFYPEER=0 and SSL_VERIFYHOST=0 — TLS peer and hostname verification are fully disabled. An on-path attacker can then present forged certificates for any hostname pyload fetches. This is a direct continuation of the fix family CVE-2026-33509 / CVE-2026-35463 / CVE-2026-35464 / CVE-2026-35586, each of which patched a different missed option in the same allowlist. This vulnerability is fixed in 0.5.0b3.dev100.