CVE-2025-41351 identifies a vulnerability in Funambol Cloud Server version 30.0.0.20 related to CWE-649, which concerns reliance on obfuscation or encryption of security-relevant inputs without accompanying integrity verification. Specifically, the vulnerability allows a Padding Oracle Attack against the thumbnail display URL functionality. In this context, the application generates 'self-signed' access URLs by encrypting parameters that control access to resources. However, because the system does not verify the integrity of these encrypted parameters, an attacker can use the padding oracle technique to iteratively decrypt and encrypt these parameters. This enables the attacker to craft valid access URLs, potentially bypassing intended access controls. The attack vector is network-based (AV:N), requires high attack complexity (AC:H), no privileges (PR:N), no authentication (AT:N), but requires user interaction (UI:P). The vulnerability impacts confidentiality (VC:H) but not integrity or availability. No patches are currently available, and no known exploits have been reported in the wild. The vulnerability was reserved in April 2025 and published in January 2026. The lack of integrity checking on encrypted inputs is a critical design flaw that undermines the security of the access URL mechanism, exposing sensitive data and potentially enabling unauthorized access to cloud resources managed by Funambol Cloud Server.

For European organizations, this vulnerability poses a risk to the confidentiality of sensitive data accessed or synchronized via Funambol Cloud Server. Attackers exploiting this flaw could decrypt encrypted URL parameters, potentially gaining unauthorized access to cloud resources or user data. This could lead to data leakage, privacy violations, and compliance issues under regulations such as GDPR. Although the attack requires user interaction and has high complexity, targeted phishing or social engineering campaigns could facilitate exploitation. The absence of integrity checks means that attackers can manipulate encrypted parameters to escalate access or bypass security controls. Organizations relying on Funambol for cloud synchronization or mobile device management may face operational disruptions or reputational damage if exploited. The medium severity rating reflects these risks balanced against the complexity and interaction requirements. Given the increasing reliance on cloud services in Europe, especially in sectors like finance, healthcare, and government, the impact could be significant if left unmitigated.

1. Implement integrity verification mechanisms such as HMAC or authenticated encryption (e.g., AES-GCM) on all encrypted parameters used in access URLs to prevent padding oracle attacks. 2. Restrict access to the thumbnail display URL endpoint by enforcing strict access controls, IP whitelisting, or network segmentation to limit exposure. 3. Monitor and log all access to thumbnail URLs and analyze logs for unusual patterns indicative of padding oracle exploitation attempts. 4. Educate users to recognize and avoid phishing attempts that could trigger user interaction required for exploitation. 5. Coordinate with Funambol to obtain patches or updates addressing this vulnerability as soon as they become available. 6. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block malformed or suspicious encrypted URL parameters. 7. Conduct regular security assessments and penetration tests focusing on encrypted input handling and URL parameter security. 8. If immediate patching is not possible, disable or limit the use of the thumbnail display URL feature temporarily to reduce attack surface.