Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAccess public share and obtain oxi_shares cookie
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ExploitOwner adds password protection to share
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ExecutionReplay cookie via GET /api/files/{id}
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ImpactRead shared files despite new password
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization logic validation
MITRE ATT&CK
1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | The attacker must already hold a valid oxi_shares share-ring cookie that was granted while the targeted share was still public (before the owner enabled password protection), and that cookie must remain valid. Exploitation is then performed by replaying that cookie against GET /api/files/{id}. Limiting factors: the attacker must have had prior anonymous access to the specific share before it was password-protected (reflected as AT:P in the CVSS 4.0 vector), so users who never accessed a share before its password was set cannot leverage this; impact is confined to reading shared file content and folder listings (no write/modify or availability impact). Affected versions are OxiCloud 0.9.1 through 0.9.3. |
| Impact | The input CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N/VC:L) yields 6.3 (Medium), and the signals are internally consistent: network-reachable (AV:N) and unauthenticated (PR:N), but gated by an attack requirement (AT:P) and limited to low confidentiality impact (VC:L) with no integrity or availability effect. The AT:P flag is the decisive signal - exploitation is not opportunistic because the attacker must already possess a valid oxi_shares share-ring cookie issued before the owner enabled password protection, which inherently narrows the population to parties who previously accessed the share. There is no CISA KEV listing, so this is NOT confirmed actively exploited. No EPSS score was provided in the input, so probabilistic exploitation likelihood cannot be quantified or compared here. No SSVC decision data was provided. A detailed third-party technical writeup (hackmd) and vulnerable source-code line references exist, but no weaponized/working exploit code is flagged in the input. Net assessment: a real but modest-priority confidentiality bug - meaningful for anyone relying on OxiCloud password protection to retroactively revoke prior anonymous access, but not a broad unauthenticated-RCE-class emergency. Prioritize patching for exposed instances; do not treat as a drop-everything issue absent KEV/EPSS escalation. |
| Exploit ScenarioDerived | An anonymous visitor accesses a public OxiCloud share and is issued an oxi_shares share-ring cookie. The share owner later adds password protection expecting to revoke public access, but the visitor - still holding the old cookie - continues to issue GET /api/files/{id} requests and reads the supposedly protected files and folder listings. A detailed technical writeup documenting the flaw is publicly available, though no packaged exploit tool is indicated in the input. |
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Alert meAnalysisAIv1 – Oct 15, 2026
OxiCloud 0.9.1 through 0.9.3 fails to revoke previously issued anonymous share grants when a share owner turns on password protection, so anyone still holding an oxi_shares share-ring cookie can continue reading shared files and folder listings through GET /api/files/{id} (CVSS 6.3, Medium; CWE-863). Exploitation is unauthenticated (PR:N) but gated by an attack requirement (AT:P): the attacker must have already accessed that specific share while it was public and must still possess the resulting cookie, and the resulting impact is limited to disclosure of shared content with no integrity or availability effect. No public exploit identified at time of analysis.
RemediationAI
No vendor-released patch identified at time of analysis, so mitigation depends on configuration and operational controls rather than an upgrade. The cleanest workaround is to never toggle password protection onto an already-public share: delete the existing share and create a fresh one, because new share identifiers invalidate previously issued oxi_shares cookies - the trade-off is that links and bookmarks already distributed to legitimate recipients stop working and must be reissued. As a stopgap, restrict anonymous reachability of the /api/files/{id} endpoint (via reverse-proxy rule or firewall ACL) to trusted networks, which removes internet exposure but also disables legitimate public sharing for all users. Administrators can additionally rotate or clear client-side oxi_shares cookies and monitor access logs for GET /api/files/ requests that carry an oxi_shares cookie against shares already marked password-protected, since such requests are the exploitation signature. Track the vendor repository at https://github.com/AtalayaLabs/OxiCloud and the advisory at https://www.vulncheck.com/advisories/oxicloud-0.9.1-through-0.9.3-incorrect-authorization-via-share-ring-cookie for the eventual fix, which must revoke existing share-ring entries at the moment password protection is enabled.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
OxiCloud is a Rust-based self-hosted file sharing and sync service from AtalayaLabs, tracked under CPE cpe:2.3:a:atalayalabs:oxicloud with a wildcard version and represented in the repository by src/application/services/share_service.rs (grant creation) and src/infrastructure/services/share_ring.rs (cookie validation). The share-ring mechanism issues an oxi_shares cookie to anonymous visitors of a public share, and that cookie is subsequently accepted as a bearer-style authorization token on requests to GET /api/files/{id}. The defect is that the authorization decision is evaluated only when a grant is minted: enabling password protection adds a check for new visitors, but existing ring entries are never invalidated, which is the classic CWE-863 incorrect authorization pattern of checking an entitlement at issuance time and never re-checking it when the security context changes. The assessed CVSS 3.1 vector (AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N) and the reported CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N/VC:L) agree that the flaw is network-reachable and unauthenticated but requires a pre-existing, still-valid cookie from a share that was public before the password was set, with impact confined to read-only exposure of shared file content and directory listings.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Pre-existing share-ring cookie from prior public access is a precondition outside attacker control (AC:H), no authentication needed (PR:N), and only read access to shared content results (C:L, I:N, A:N).
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
DescriptionCVE.org
OxiCloud 0.9.1 through 0.9.3 contains an incorrect authorization vulnerability that allows anonymous visitors to keep share access after password protection is added. Attackers holding an existing oxi_shares share-ring cookie can request content via GET /api/files/{id} to read shared files or folder contents despite the new password.
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.
EUVD-2026-102486
GHSA-j8xc-5qc2-7pc3
NVD
CVE.org
EPSS
VulDB
Exploit-DB