CVE-2026-92120 in Allura
Summary
by MITRE • 10/12/2026
OAuth1 Request Replay Attack vulnerability in Apache Allura.
This issue affects Apache Allura: through 1.21.0.
Users are recommended to upgrade to version 1.22.0 which fixes the issue.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified as an OAuth1 Request Replay Attack within Apache Allura represents a critical failure in the implementation of authentication protocols, specifically affecting versions through 1.21.0. This flaw stems from insufficient validation mechanisms regarding the uniqueness and temporal validity of cryptographic signatures used during the OAuth1 authorization process. In standard OAuth1 implementations, security relies heavily on nonces and timestamps to ensure that each request is unique and has not been previously processed by the server. The absence or improper enforcement of these checks in Apache Allura allows an attacker to capture a valid, authenticated HTTP request containing a legitimate signature and subsequently resend it multiple times without modification. This capability fundamentally undermines the integrity of the authentication system, as the server cannot distinguish between a fresh user action and a repeated transmission of a previously authorized command.
From a technical perspective, this vulnerability is classified under CWE-294, which describes Improper Authentication: Acceptance of a Replayed Request. The core issue lies in the application's failure to maintain state regarding consumed nonces or to strictly enforce timestamp windows that prevent replay attacks. When an OAuth1 request is made, it includes parameters such as oauth_nonce and oauth_timestamp. A secure implementation must verify that the nonce has not been seen before within a specific time window defined by the server's configuration. In vulnerable versions of Apache Allura, this verification step is either missing or bypassed, allowing an attacker who intercepts network traffic to replay the captured request payload. This can be executed using automated tools that capture and resend HTTP packets with identical headers and bodies, effectively tricking the application into processing duplicate actions as if they were new, legitimate user interactions.
The operational impact of this vulnerability is severe, particularly in a collaborative development platform like Apache Allura where administrative privileges and data integrity are paramount. An attacker can exploit this flaw to perform unauthorized actions on behalf of authenticated users or administrators. This includes but is not limited to creating malicious projects, modifying project settings, deleting repositories, posting spam content, or altering user permissions. Because the replayed request carries a valid signature generated by an authorized token, the server processes it as authentic. This can lead to significant data loss, unauthorized access to sensitive codebases, and potential compromise of the entire instance if administrative accounts are targeted. Furthermore, this vulnerability facilitates automated abuse at scale, allowing attackers to spam forums or flood issue trackers without needing to bypass complex anti-bot measures, since they are simply replaying valid authenticated sessions.
This attack vector aligns with MITRE ATT&CK technique T1078, specifically Valid Accounts and potentially T1539 if it involves stealing session tokens for later use, though the primary mechanism here is direct request replay rather than token theft per se. It also relates to CWE-347 regarding Improper Verification of Cryptographic Signature, as the signature itself is valid but its context (uniqueness) is ignored. To mitigate this risk, organizations running Apache Allura must upgrade immediately to version 1.22.0 or later, where the developers have implemented proper nonce tracking and timestamp validation logic. For environments that cannot be upgraded instantly due to operational constraints, network-level mitigations such as deep packet inspection firewalls can help detect repeated identical requests from a single source within short timeframes. Additionally, ensuring that OAuth tokens are scoped with minimal necessary privileges reduces the blast radius if an attacker successfully replays a request. Regular auditing of access logs for patterns indicative of replay attacks, such as high volumes of identical signature values or nonces, is also recommended to detect ongoing exploitation attempts.