CVE-2026-71294
HIGHCVE-2026-71294 is a high-severity (CVSS 7.6) Deserialization of Untrusted Data vulnerability. O3 Security confirms whether CVE-2026-71294 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cotonti CMS's Comments plugin deserializes user-supplied data without restricting the classes that may be instantiated. In plugins/comments/controllers/actions/CreateAction.php, a `ci`…
Description
Cotonti CMS's Comments plugin deserializes user-supplied data without restricting the classes that may be instantiated. In plugins/comments/controllers/actions/CreateAction.php, a ci POST parameter obtained via cot_import('ci', 'P', 'TXT') (trim-only sanitization) is passed to unserialize(base64_decode($ci)) with no allowed_classes restriction, reachable by any member with write access to comments (the default Auth_members => 'RW' setting in plugins/comments/comments.setup.php). In plugins/comments/controllers/actions/EditAction.php, a cb parameter is similarly deserialized via unserialize(base64_decode($this->comeback)) in prepareComeBack(), reachable by any member editing their own comment. Because unserialize() is called without allowed_classes, an attacker can construct a serialized PHP object of any class loaded by Cotonti (a PHP Object Injection primitive). This was demonstrated in practice using Cotonti's own MySQL_cache class: a crafted serialized MySQL_cache object, once deserialized and later garbage-collected, triggers its __destruct()->flush() chain, causing an attacker-controlled INSERT INTO cot_cache with attacker-chosen row values — confirming genuine POP-chain exploitation, with further impact (including potential RCE) contingent on other gadget chains available in a given Cotonti installation's loaded classes. A third sink in DeleteAction.php contains the identical unserialize() pattern but is gated behind an admin-only authorization check and is not reachable by ordinary members.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-71294 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-71294 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-71294. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-71294 in your dependencies?
O3 detects CVE-2026-71294 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.