Security readout for executives and security teams
Plain-English summary
A remote person can self-register an account whose name differs from another user only by letter case. On case-insensitive storage, both accounts may reach the same folder, allowing the second user to view, alter, or delete the first user’s files. No victim action or pre-existing attacker account is required.
Executive priority
Treat affected, reachable deployments as an immediate remediation priority because unauthorized users could compromise customer or business files. Rapidly identify installations meeting all required conditions, upgrade them, and investigate case-colliding accounts. Other deployments should still confirm version and configuration promptly rather than assuming they are safe.
Technical view
FileBrowser before 2.63.19 compares persisted home-directory scopes case-sensitively while some filesystems resolve paths case-insensitively. With Signup and CreateUserDir enabled, distinct account records can consequently map to one physical directory. The resulting authenticated access can compromise file confidentiality, integrity, and availability.
Likely exposure
Exposure requires FileBrowser before 2.63.19, enabled Signup and CreateUserDir settings, and a case-insensitive filesystem beneath the configured root. Windows with NTFS is confirmed. Risk is greatest where untrusted users can reach self-registration. Deployments lacking any required condition are not described as exploitable by this issue.
Exploitation context
The supplied record rates this CVSS 4.0 score 9.2, with high confidentiality, integrity, and availability impact. Exploitation requires specific configuration and filesystem conditions but no prior account or victim interaction. The CVE is not listed as KEV, and the supplied sources provide no evidence of active exploitation.
Researcher notes
CWE-178 captures the core inconsistent case handling. The security boundary fails because account identity remains case-distinct while filesystem path identity does not. Assessment should distinguish confirmed Windows/NTFS exposure from other platforms: the bundle confirms NTFS but does not establish every case-insensitive filesystem or configuration as vulnerable.
Mitigation direction
- Upgrade FileBrowser to version 2.63.19 or later using vendor-supported packages.
- If immediate upgrading is impossible, disable Signup or CreateUserDir to remove a required condition.
- Restrict self-registration access to trusted users until remediation is verified.
- Investigate potentially colliding accounts and shared-directory file changes before restoring normal access.
Validation and detection
- Confirm the installed FileBrowser version is 2.63.19 or later.
- Verify whether Signup and CreateUserDir are enabled in each deployment.
- Determine whether FileBrowser's root resides on a case-insensitive filesystem.
- Identify registered usernames that differ only by letter case.
- Review relevant access records and file histories for unexpected reading, modification, or deletion.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-178: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-72836 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.2CriticalVector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- GitHub Security Advisory (GHSA-576v-w77m-gr84)CVE reference, VulnCheck · vendor-advisory
- Patch CommitCVE reference, VulnCheck · patch
- VulnCheck Advisory: FileBrowser before 2.63.19 Case Sensitivity Authentication BypassCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Handling of Case Sensitivity
Improper Handling of Case Sensitivity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.