The vulnerability CVE-2026-89321 could compromise system integrity but typically requires user interaction to be exploited.
Status: Received on 14 Sep 2026, 09:17 UTC
Published on: 14 Sep 2026, 09:17 UTC
CVSS Release: version 3
emo@eclipse.org
Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVE-2026-89321: 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 exploitability of CVE-2026-89321 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2026-89321 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-89321, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-89321, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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