Ad Inserter EUVD-2026-98345

Requires an authenticated session at subscriber level or above (CVSS PR:L) on a WordPress site running Ad Inserter - Ad Manager & AdSense Ads version 2.8.18 or earlier; disclosure occurs through the plugin's ai_wp_footer_hook code path against default configurations, with no user interaction and no special plugin feature toggle named in the description. The main limiting factor is the account requirement: sites that disable open user registration confine this to existing trusted users, whereas sites permitting self-service subscriber signup are exploitable by any registrant. Sensitivity of the leak scales with the environment - exposure of other plugins' API tokens only matters where such integrations exist.

This is a genuine but moderate-priority issue, not a top-tier emergency. The CVSS 3.1 base score is 4.3 (Medium) with vector AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - network-reachable, low complexity, but requiring authentication (PR:L, subscriber-level) and limited to confidentiality-only impact. No EPSS score, CISA KEV listing, or public POC was provided in the input, so exploitation likelihood signals are absent rather than reassuring: no public exploit identified at time of analysis. The principal factor elevating real risk above the raw score is the breadth of exposed data described - not just version strings and server internal IP, but API tokens and underscore-prefixed protected post meta written by OTHER plugins, plus hardening constants and the plugin block matrix. That breadth means the vendor's C:L rating is arguably conservative; leaked third-party API tokens can enable lateral movement to external services, which looks closer to a serious confidentiality loss. The limiting factor is the authentication requirement: WordPress sites that freely allow subscriber self-registration are meaningfully exposed, while sites with registration disabled face a much smaller attack surface. Net: prioritize patching on multi-user/open-registration sites; treat as routine hygiene on single-admin sites.

An attacker registers (or already holds) a low-privileged subscriber account on a WordPress site running Ad Inserter ≤2.8.18, then triggers the ai_wp_footer_hook output path to harvest the site's server internal IP, PHP/WordPress/theme versions, hardening constants, and all post meta - including protected underscore-prefixed keys containing API tokens from other plugins. The harvested tokens and configuration intelligence are then reused to pivot against connected third-party services or to tailor follow-on attacks. No public exploit code was identified in the provided data, and exploitation requires only an authenticated low-privilege session with no user interaction.