CVE-2026-42312

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:

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:

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:

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):

# 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.

• 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.

A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.

CVE-2026-42312 has a CVSS score of 6.8 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.5.0b3.dev100); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-42312? CVE-2026-42312 is a medium-severity missing authentication for critical function vulnerability in pyload-ng (pip), affecting versions <= 0.5.0b3.dev99. It is fixed in 0.5.0b3.dev100. A critical operation is accessible without requiring any authentication.
2. How severe is CVE-2026-42312? CVE-2026-42312 has a CVSS score of 6.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of pyload-ng are affected by CVE-2026-42312? pyload-ng (pip) versions <= 0.5.0b3.dev99 is affected.
4. Is there a fix for CVE-2026-42312? Yes. CVE-2026-42312 is fixed in 0.5.0b3.dev100. Upgrade to this version or later.
5. Is CVE-2026-42312 exploitable, and should I be worried? Whether CVE-2026-42312 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-42312 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-42312? Upgrade pyload-ng to 0.5.0b3.dev100 or later.