Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessIdentify target YesWiki instance
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DeliveryEnumerate restricted page tag and file name
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ExploitRequest attachment download handler directly
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ExecutionBypass missing read ACL check
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ImpactRetrieve confidential attachment
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
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 | No special configuration is required beyond running an affected YesWiki version (any release before 4.6.7) that serves attachments on read-restricted pages; exploitation works against default deployments where page-level read ACLs are relied upon to protect uploaded files. The attacker must know or enumerate two values: the target page's tag and the specific file parameter (attachment name), since the download handler is requested directly with these. The practical limiting factor is this knowledge requirement - attachments on pages whose tag and file names are unknown and non-guessable are harder to retrieve - but there is no authentication, privilege, or user-interaction barrier. |
| Impact | This is a credible, actionable priority rather than a merely high-scoring paper risk. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N) describes a network-reachable flaw that requires no authentication, no privileges, no user interaction and no special attack prerequisites, with a high confidentiality impact (VC:H) and no integrity or availability impact - fully consistent with the description of an unauthenticated ACL bypass that leaks confidential attachments. No EPSS score, SSVC decision, KEV listing, or POC was provided in the input, so exploitation likelihood cannot be quantified from probabilistic signals; the absence of these is itself a data gap, not evidence of low risk. Exploitation status is therefore 'no public exploit identified at time of analysis.' The main factor that tempers overall severity is the limited blast radius: the vulnerability only discloses information (read access to restricted attachments) and cannot by itself modify or destroy data. Reported by VulnCheck and documented in an official vendor GHSA advisory, the technical facts are well-corroborated, but real-world exploitation volume is unknown and should be judged against the product's modest deployment footprint rather than assumed to be widespread. |
| Exploit ScenarioDerived | An unauthenticated attacker who learns or guesses the page tag and attached file name of a read-restricted YesWiki page sends a direct request to the attachment download handler with those parameters. Because the handler fails to enforce the page's read ACL, the server returns the confidential attachment, leaking sensitive documents without any login. No public exploit code was identified, but the attack requires only a crafted HTTP GET and is trivial to reproduce. |
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Alert meAnalysisAIv1 – Oct 02, 2026
Unauthenticated attachment disclosure in YesWiki before 4.6.7 allows remote attackers to bypass page read ACLs and retrieve confidential files by directly invoking the attachment download handler with a known page tag and file parameter. The missing authorization check (CWE-862) yields high confidentiality impact with no integrity or availability impact, reflected in the independent CVSS 3.1 assessment of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N) and the CVSS 4.0 score of 8.7. No public exploit code has been identified at time of analysis, but exploitation requires only knowledge of the page tag and attachment name and works against default deployments where ACLs are the sole protection.
RemediationAI
Vendor-released patch: upgrade to YesWiki 4.6.7 or later, as documented in the vendor security advisory (GHSA-7cj2-9pgf-vcw2). If immediate upgrade is not possible, restrict access to the attachment download handler at the web server or reverse proxy layer-for example, require authentication for the handler's URI pattern or block direct requests to it-though this may disrupt legitimate download links and should be tested against normal workflows. Additionally, avoid relying solely on page read ACLs to protect sensitive attachments: move confidential files to a location outside YesWiki's attachment directory or store them on a separate authenticated file service, and audit existing read-restricted pages for attachments that may already have been exposed.
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
YesWiki is a PHP-based wiki/CMS that stores uploaded files as page attachments and serves them through a dedicated download handler. CWE-862 (Missing Authorization) describes the root cause: the handler fails to verify that the requesting user has read permission on the page associated with the attachment, so it returns the file regardless of ACLs. The CPE cpe:2.3:a:yeswiki:yeswiki:*:*:*:*:*:*:*:* and EUVD data (affected versions 0 <4.6.7) confirm all releases prior to 4.6.7 are impacted. Because the handler is reachable without authentication (CVSS PR:N), the only barrier is the attacker's ability to know or guess the page tag and the exact file parameter, both of which are supplied in the request.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Remote unauthenticated request with no user interaction bypasses read ACLs (AV:N/AC:L/PR:N/UI:N); impact is information disclosure only, so C:H and I:N/A:N.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
2DescriptionCVE.org
YesWiki before 4.6.7 contains a missing authorization vulnerability in the attachment download handler that allows unauthenticated attackers to bypass page read ACLs. Attackers can request the download handler with a known page tag and file parameter to retrieve confidential attachments from read-restricted pages.
Technical POC Analysis
CWE-862 (Missing Authorization).
Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.
Executive ViewAI
YesWiki installations at versions below 4.6.7 expose stored attachments to anyone who can reach the site, because the file download handler skips the access checks that normally protect pages. Any confidential material uploaded to a wiki page - board papers, contracts, HR files, credentials, client data - can be retrieved by an unauthenticated visitor who knows or guesses the page tag and file name. This places regulated and sensitive content on internet-facing wikis at risk of undetected bulk collection by outside parties, with no integrity or availability effects to trip alarms.
Apply vendor patch.
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.
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Unauthenticated attackers can delete or overwrite federated entries in YesWiki instances before 4.6.7 that have Activity
EUVD-2026-91395
GHSA-m45w-rvq4-f22g
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB