Eclipse OpenVSX up to 1.1.x Zip Extraction /vscode/unpkg Files.copy resource consumption

Summaryinfo

A vulnerability marked as problematic has been reported in Eclipse OpenVSX up to 1.1.x. This affects the function Files.copy of the file /vscode/unpkg of the component Zip Extraction. This manipulation causes resource consumption. This vulnerability is tracked as CVE-2026-89321. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Eclipse OpenVSX up to 1.1.x. It has been declared as problematic. Affected by this vulnerability is the function Files.copy of the file /vscode/unpkg of the component Zip Extraction. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

Publishing limits the compressed size of a VSIX (ovsx.publishing.max-content-size, 512 MB by default) but nothing limited how large an entry becomes when opened. On the first request to /vscode/unpkg/{namespace}/{extension}/{version}/{path}, WebResourceService opened the entry with ZipFile.getInputStream() and passed the decompressed stream to Files.copy(), which ran to the end of the stream without counting bytes written. The result was cached under java.io.tmpdir, and that cache evicted by entry count (150), not by size, so it placed no bound on disk usage. A publisher with access only to their own namespace could therefore upload a small, highly compressible VSIX and cause the server to write far larger files to the temp filesystem — repeating with different files or versions, since a repeat request is served from the cache. Impact observed: the temp filesystem filled; requests for files not already cached returned 500 with No space left on device; a failed extraction left a partial cache file that blocked later attempts at that path; publishing failed with Failed to read extension file. Metadata and already-cached files kept working, and the server did not stop. Triggering the extraction needs no authentication — only the upload does.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-89321 since 09/11/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 1.2.0 eliminates this vulnerability.

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Productinfo

Vendor

• Eclipse

Name

• OpenVSX

Version

• 1.0
• 1.1

License

• open-source

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CPE 2.2info

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