metacat: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-47754 is a critical-severity improper limitation of a pathname to a restricted directory vulnerability in metacat from NCEAS, with a CVSS 3.1 base score of 9.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected metacat versions: < 3.0.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of metacat you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N. Scored by CNA (github.com).
Official description
Metacat is data repository software that helps researchers preserve, share, and discover data. Versions 2.x through 2.19.1 and all 1.x versions contain an unauthenticated path traversal in the `archiveEntryName` parameter of the `action=read` endpoint that is part of the original 1.x Metacat API. `ArchiveHandler.readArchiveEntry()` concatenates the user-supplied parameter into a filesystem path without validation, and the surrounding `hasReadPermission()` check is commented out. An unauthenticated remote attacker can read any file accessible to the Tomcat process by sending a single GET request. Proof-of-concept exploits have been demonstrated and verified against this vulnerability, and it should be considered easily exploitable for any Metacat deployment < 3.0.0 by any user with access to the 1.x API. Through this vulnerability, production 2.x deployments are exposed to credential theft, client certificate and private key exfiltration enabling member node impersonation within the federation, embargoed research data disclosure, and broad system reconnaissance. Given Metacat's deployment footprint across the DataONE network of repositories and federally funded research programs, the population of exposed 2.x instances is non-trivial. The vulnerability was eliminated in Metacat version 3.0.0 and after by eliminating the entire Metacat 1.x API that exposed this vulnerability. The vulnerability was remediated in April 2024 with the release of Metacat 3.0.0, which removed the legacy Metacat API including ArchiveHandler.java. The commit message and issue reference architectural cleanup, not a security fix, and no advisory or CVE was issued. The 2.x branch was not and will not be backported, as is standard practice in Metacat, which only supports the most current release. 2.19.1 remains vulnerable with identical code and is beyond its supported lifetime. As a workaround, disable or restrict 1.x API servlets. Because the vulnerable 1.x API is no longer used or necessary in most Metacat deployments, restricting access to the old API endpoints can reduce or eliminate exposure for 2.19.x deployments. After removing those features, restart Tomcat or whichever software is hosting the servlets.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Other vulnerabilities in metacat
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.1 High severity
- 8.1 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
Spotted an error? Tell us.