Adobe Connect CVE-2026-27303

Exploitation targets Adobe Connect servers accessible over network (AV:N in CVSS vector) running versions 12.10 or earlier. CRITICAL CONFLICT IN SOURCE DATA: CVSS vector specifies UI:R (user interaction required), but the CVE description explicitly states 'Exploitation of this issue does not require user interaction.' Organizations must consult Adobe Security Bulletin APSB26-37 to determine accurate exploitation prerequisites. If UI:R is correct, attack requires victim user action such as clicking a malicious link or processing attacker-controlled content within Adobe Connect. If description is correct (no user interaction), exploitation is possible through direct server-side request processing. No authentication required (PR:N) against default configurations. What LIMITS exploitation: Low attack complexity (AC:L) suggests straightforward exploitation once prerequisites understood, but SSVC automatable=no indicates some manual attacker effort needed, possibly requiring knowledge of specific Adobe Connect API endpoints or data formats. Exploitation likelihood reduced for deployments with network access controls restricting Connect servers to internal networks only. Changed scope indicates vulnerability exists in a component handling external input with elevated privileges or insufficient sandboxing.

Real-world risk assessment reveals conflicting signals requiring careful interpretation. CVSS 9.6 (Critical) with AV:N/AC:L/PR:N indicates network-accessible, low-complexity exploitation without authentication - traditionally high-risk parameters. However, the UI:R component requires user interaction, which contradicts the description stating 'does not require user interaction.' This discrepancy must be resolved with Adobe's advisory APSB26-37 to determine actual attack prerequisites. EPSS 1.50% (81st percentile) suggests moderate exploitation likelihood despite critical CVSS score, indicating this may not be trivially exploitable or widely attractive to attackers. SSVC framework assessment shows exploitation=none (no confirmed exploitation), automatable=no (requires some attacker effort), technical impact=total (complete system compromise possible). The changed scope significantly elevates impact beyond typical web application RCE. CISA has not added this to KEV, confirming no widespread active exploitation. Priority assessment: HIGH for internet-facing Adobe Connect deployments, MEDIUM for internal-only instances with network segmentation. The deserialization attack class is well-understood by sophisticated actors, making this a viable target once technical details from APSB26-37 become public. Critical conflict requiring verification: CVSS vector UI:R versus description claiming no user interaction - defenders must confirm actual exploitation conditions from vendor advisory.

An unauthenticated remote attacker identifies an Adobe Connect server exposed to the internet and crafts a malicious serialized object payload containing executable code. The attacker sends this payload via HTTP request to a Connect endpoint that processes serialized data (likely meeting/session management or file upload functionality). Adobe Connect deserializes the untrusted payload without validation, instantiating the attacker's malicious objects and triggering arbitrary code execution in the application context. Due to changed scope (S:C), the attacker leverages the initial foothold to escape application constraints and compromise the underlying server or adjacent systems, potentially gaining full system control, accessing sensitive meeting recordings and user data, or pivoting to other internal resources. No public proof-of-concept identified at time of analysis, but deserialization exploitation techniques are well-documented in security research.