CVE-2026-116825 in YesWiki
Summary
by MITRE • 10/27/2026
YesWiki from 4.6.2 before 4.7.0 lacks replay protection in HttpSignatureService::verifySignature(), which never validates the Date header or tracks seen signatures. Attackers who capture a signed request to the /api/forms/{formId}/actor/inbox endpoint can replay it later to re-execute Delete, Update, Follow, or Undo actions.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability in YesWiki versions prior to 4.7.0 represents a critical failure in cryptographic message authentication and session management within the HttpSignatureService component. Specifically, the verifySignature method responsible for validating incoming API requests fails to implement essential replay protection mechanisms. In secure systems utilizing HTTP signatures or similar token-based authentication schemes, it is standard practice to validate temporal constraints such as the Date header to ensure a request was made recently, thereby limiting the window of opportunity for an attacker to intercept and reuse credentials. Furthermore, robust implementations maintain a record of previously processed signature identifiers or nonces to detect duplicate submissions. YesWiki’s implementation neglects both of these critical checks, leaving the integrity and confidentiality of user actions severely compromised by allowing identical signed requests to be executed multiple times without detection.
This technical flaw directly impacts the /api/forms/{formId}/actor/inbox endpoint, which handles sensitive administrative and social interactions within the wiki platform. Because there is no validation of the Date header or tracking of seen signatures, an attacker who possesses network-level access can capture a valid signed request packet in transit using standard man-in-the-middle techniques. Once captured, this packet can be replayed at any later time to trigger destructive actions such as deleting content, updating records with malicious data, following other users without consent, or undoing legitimate user activities. The absence of temporal validation means that even if the signature itself remains cryptographically valid for an extended period, the system cannot distinguish between a fresh action and a recycled one, effectively granting persistent unauthorized access to any captured session token until it expires through external factors rather than internal logic.
The operational impact of this vulnerability is significant, particularly in collaborative environments where multiple users interact with forms and each other’s data. An attacker could systematically replay delete commands to erase important wiki pages or form submissions, leading to permanent data loss if backups are not available. Similarly, the ability to re-execute follow actions allows for spamming or unauthorized association of user accounts, while undoing legitimate changes disrupts workflow integrity and audit trails. Since these operations often require elevated privileges associated with the authenticated actor, successful exploitation effectively bypasses access controls by leveraging valid credentials obtained through network interception rather than brute force or credential theft.
To mitigate this risk, immediate updates to YesWiki version 4.7.0 or later are required as they address these deficiencies in signature verification logic. In environments where upgrading is not immediately feasible, administrators should implement reverse proxy rules that enforce strict rate limiting and request deduplication based on source IP and timestamp windows for the affected API endpoints. Additionally, ensuring all communications occur over TLS with strong cipher suites reduces the likelihood of initial packet capture by attackers. From a standards perspective, this vulnerability aligns with CWE-294 which describes authentication bypass issues related to capturing and replaying messages, as well as CWE-347 regarding insufficient verification of data authenticity. In terms of offensive security frameworks, this flaw facilitates MITM-REPLAY attacks under the ATT&CK technique T1557, highlighting the necessity for implementing nonce-based or timestamp-bound validation in all state-changing API endpoints to preserve system integrity and prevent unauthorized replay of authenticated requests.