Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate as low-privilege project member
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ExploitObtain victim's pending attachment pk UUID
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ExecutionSend PATCH with attacker-controlled issue_id and victim pk
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ImpactServer reassigns created_by, hijacking attachment ownership
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Object-level authorization, IDOR prevention
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| Exploitation Conditions | Requires an authenticated account that is a member of the target Plane project (PR:L), so this is not remote-unauthenticated. The attacker must target an attachment that is still in the PENDING state (not yet confirmed as uploaded) - confirmed attachments are unaffected - and must know the victim attachment's pk UUID, since the server matches on pk, workspace, and project_id. These factors (authenticated project membership, the narrow pending-upload window, and the need for an unguessable UUID) materially limit realistic exploitation despite the network attack vector. No special non-default configuration is needed; the flaw is present in the default V2 issue-attachment PATCH endpoint in versions prior to 1.4.0. |
| Impact | This is a genuine but moderate-priority authorization flaw (CWE-639, insecure direct object reference). The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L, base 7.1) is consistent with the description: a network-reachable API endpoint, low complexity, and an authenticated low-privilege project member required (PR:L). There is no confidentiality impact (C:N) because the bug reassigns attachment ownership rather than disclosing content; integrity is rated high (I:H) and availability low (A:L) reflecting unauthorized modification and loss of ownership for the legitimate user. No EPSS score was supplied and the CVE is NOT on CISA KEV, so there is no evidence of active exploitation - status is 'no public exploit identified at time of analysis'. A key mitigating nuance the raw CVSS does not capture: exploitation is limited to attachments still in the PENDING (not-yet-confirmed-uploaded) state and requires the attacker to know the target attachment's pk UUID, which is not easily enumerable. The vendor fix commit and PR diff are public, which lowers the bar for a patch-diffing attacker even though no weaponized POC is published. Overall this is a legitimate authorization bug worth patching but not an emergency; the 7.1 score slightly overstates practical risk given the pending-only window and UUID prerequisite. |
| Exploit ScenarioDerived | An authenticated low-privilege member of a Plane project learns or obtains the pk UUID of another user's attachment that is still in the pending (unconfirmed-upload) state. The attacker sends a V2 issue-attachment PATCH request supplying an issue_id they control in the URL but the victim's attachment pk, and because the server matches only pk, workspace, and project_id, it reassigns created_by to the attacker, transferring ownership. No public POC is identified, though the fix commit and PR diff are publicly available. |
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Alert meAnalysisAIv1 – Oct 05, 2026
An insecure direct object reference (IDOR) in Plane prior to 1.4.0 lets an authenticated member of a project reassign ownership of another user's issue attachment by supplying a pk UUID in the V2 issue-attachment PATCH request. Because the endpoint validates only pk, workspace, and project_id while ignoring the issue_id present in the URL, an attacker with project membership (CVSS PR:L, network vector) can target any attachment still in the PENDING, not-yet-confirmed upload state and set created_by to their own account, thereby taking control of it; confirmed attachments are unaffected, and exploitation also requires knowing the victim's unguessable UUID. The flaw is a genuine but moderate-priority authorization issue (CWE-639) with no public exploit identified at time of analysis, and it is fixed in the vendor's 1.4.0 release.
RemediationAI
Vendor-released patch: 1.4.0 - upgrade Plane to v1.4.0 or later, which adds issue_id to the FileAsset lookups and removes the created_by reassignment (see https://github.com/makeplane/plane/releases/tag/v1.4.0, PR #9315, and commit 5829f0febf0739494d576b60d4943d10d236bc96; advisory GHSA-5mxw-g5mw-3v3w). Because the exploitation window is narrow - the attacker must be an authenticated project member and must know the victim attachment's UUID while it is still pending - organizations that cannot immediately upgrade should treat project membership as a trust boundary: audit and minimize membership in projects handling sensitive files, and monitor server logs for PATCH requests to issue-attachment routes where the URL issue_id does not correspond to the attachment's actual issue, since that mismatch is the signature of this abuse. Temporarily disabling the V2 issue-attachment PATCH/POST flow or restricting attachment uploads to administrators would close the vector but breaks normal issue-file workflows and the pending-upload confirmation step, so use it only as a short-term containment measure. Rotating or re-verifying ownership of any attachments that were in a pending state during the exposure window is advisable, as ownership may have been silently reassigned.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
Plane is an open-source project management tool whose Django-based API stores issue files in a FileAsset model. The V2 issue-attachment PATCH view (apps/api/plane/app/views/issue/attachment.py) looked up the target record with FileAsset.objects.get(pk=pk, workspace__slug=slug, project_id=project_id), scoping the query by primary key, workspace, and project but omitting the issue_id that appears in the route. This is a classic CWE-639 authorization bypass through user-controlled key / IDOR: the URL-provided issue_id was never enforced against the object actually returned, so any attachment within the same workspace and project could be reached through an issue the attacker legitimately controls. The handler then compounded the exposure by assigning issue_attachment.created_by = request.user, transferring ownership whenever the attachment was in the pending state and had not been confirmed as uploaded. The upstream fix adds issue_id=issue_id to the PATCH, GET, POST, and DELETE lookups and removes the created_by reassignment entirely, ensuring ownership is fixed at creation time.
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
Network API, low complexity, but an authenticated project member is required (PR:L); unauthorized ownership reassignment yields I:H with A:L for the victim and no data disclosure (C:N).
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
2DescriptionCVE.org
Plane is an open-source project management tool. Prior to 1.4.0, the V2 issue-attachment PATCH endpoint accepts issue_id in the URL but omits it from the database query. A project member can use an issue_id they control in the URL while targeting another user's attachment by its pk UUID. Because the server matches only pk, workspace, and project_id, it modifies the attachment regardless of the issue_id in the URL. When the attachment is pending and has not been confirmed as uploaded, the PATCH handler sets created_by = request.user and transfers attachment ownership to the attacker. This issue is fixed in 1.4.0.
Technical POC Analysis
CWE-639, Authorization Bypass Through User-Controlled Key.
Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.
Executive ViewAI
Plane, the project-management platform used by internal teams, ships with an authorization weakness that lets an authenticated project member take ownership of a colleague's file attachment while that upload is still pending confirmation. The exposure is confined to not-yet-confirmed attachments and requires both routine project access and knowledge of an unguessable identifier, so broad opportunistic exploitation is unlikely - the credible threat is insider misuse or abuse of a compromised account against teams that store sensitive material in Plane. Leadership should care because the flaw undermines the ownership guarantees teams rely on for document custody, and remediation depends on completing a version upgrade that the provided patch field does not yet reflect as released.
Apply vendor patch (upgrade to Plane 1.4.0). If the upgrade cannot be completed immediately, restrict project membership to vetted users, disable or defer file attachment uploads on affected instances, log and alert on V2 issue-attachment PATCH requests and on any change to an attachment's created_by field, and rotate or review accounts with broad project access.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Cross-workspace authorization bypass in Plane (makeplane) prior to version 1.3.1 allows any authenticated user of one wo
Plane version 0.7.1 allows an unauthenticated attacker to view all stored server files of all users. Rated high severity
Authenticated users who can create a workspace in Plane can force the application's background worker to fetch internal-
Unauthenticated remote attackers can forge Django-signed session cookies, CSRF tokens, and password-reset tokens, and by
Workspace invitation hijacking in Plane prior to 1.4.0 lets an unauthenticated attacker take over a pending workspace in
Plane is an open-source project management tool. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploi
Plane (makeplane/plane) through version 1.4.2 makes security decisions based on the client-supplied X-Forwarded-For head
Improper authorization in Plane before 1.4.0 lets an authenticated workspace Guest hijack file assets from other project
Account takeover in Plane (makeplane) versions prior to 1.4.0 allows remote unauthenticated attackers to log in as exist
Brute-forceable magic-code email login in Plane versions prior to 1.4.0 allows unauthenticated remote attackers to guess
Server-side request forgery in Plane, the open-source project management tool, allows a low-privilege user of a connecte
Authenticated cross-workspace access control bypass in Plane (makeplane/plane) before version 1.4.0 lets any user with a
EUVD-2026-92547
NVD
CVE.org
EPSS
Vulnrichment
GitHub
VulDB
Exploit-DB