Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:NSummary
CVE-2026-40896 is a medium-severity Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367) vulnerability in Openproject Openproject. Its CVSS base score is 6.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-40896 is a vulnerability in OpenProject, an open-source web-based project management software. In versions prior to 17.3.0, users with the `manage_agendas` permission in any project can inject agenda items into meetings belonging to any other project on the same instance, including those they have no access to. This issue stems from insufficient authorization checks, mapped to CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition) and CWE-639 (Authorization Bypass Through User-Controlled Key). The vulnerability has a CVSS v3.1 base score of 6.5 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N), indicating medium severity with high integrity impact.
An authenticated attacker requires only low-privilege access, specifically the `manage_agendas` permission in a single project, to exploit this over the network with low complexity and no user interaction. No prior knowledge of the target project, meeting, or victims is needed; the attacker can blindly enumerate and inject items into every meeting instance-wide by iterating sequential section IDs, effectively spraying malicious agenda content across projects.
The OpenProject security advisory (GHSA-hh5p-gwf8-h245) and associated patch commit confirm that upgrading to version 17.3.0 resolves the issue by enforcing proper project-scoped authorization for agenda management. Security practitioners should prioritize patching affected instances and review permissions for `manage_agendas` roles.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-23870
Vulnerability Data
OpenProject is open-source, web-based project management software. Prior to version 17.3.0, a user with `manage_agendas` permission in any project can inject agenda items into meetings belonging to any other project on the instance — even projects they have no access…
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to. No knowledge of the target project, meeting, or victim is required; the attacker can blindly spray items into every meeting on the instance by iterating sequential section IDs. Version 17.3.0 patches the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V15.4.2V17.2.6
Mitigating Controls (NIST 800-53 r5) AI
Enforcing approved authorizations on every access request structurally stops a user-controlled key from reaching another user's data.
Requiring explicit access-control decisions on each request blocks unauthorized key-driven access.
A reference monitor that is always invoked and analyzable structurally eliminates the non-atomic check-then-use pattern underlying TOCTOU.
Least-privilege restrictions limit the scope of data reachable even if a key check is bypassed.
Process isolation limits the blast radius of a successful TOCTOU exploitation but does not remove the race itself.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.
Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.
Secure SDLC practices directly include coding standards and reviews that prevent TOCTOU race conditions.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect missing authorization checks but does not prevent the weakness in production.
Information access restriction explicitly enforces that users may only retrieve data they are authorized to see, directly addressing user-controlled key bypass.
Access control policy directly requires enforcement of authorization rules that prevent unauthorized access via manipulated keys.
Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.
Privileged access rights control restricts what data each user may access, mitigating direct object reference attacks.
Secure development lifecycle includes authorization design but does not itself implement runtime access checks.