Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-89321. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-89321 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

1 public PoC repositories reported; 0 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-89321 using CVSS 4.3, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

mediumpublic exploit

CVE-2026-89321

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…

Q: What is CVE-2026-89321?

CVE-2026-89321 is Publishing limits the compressed size of a VSIX (ovsx.publishing.max-content-size, 512 MB by default) but nothing limited how large an…. The supplied enrichment data classifies it as Unclassified mapped to CWE-409 CWE-409.

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.

Published Sep 14, 2026Updated Sep 14, 2026Sources: NVD, Eclipse Foundation (CNA), GitHub, GitHub Security Advisory, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Exploit code

public exploit, none observed

EPSS

ahead of 0% of scored CVEs

Affects

Eclipse Foundation

Eclipse OpenVSX

CVSS base

4.3

medium

Remediation

The vendor's own words where we have them.

Upgrade Eclipse OpenVSX to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Eclipse Foundation	Eclipse OpenVSX	0.20.0 to < 1.2.0	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

Low

Confidentiality

None

Integrity

None

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

Low

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
4.3	CVSS 3.1	medium	2.8	1.4	eclipse.org (CNA), Eclipse Foundation (CNA), GHSA

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-409 · Improper Handling of Highly Compressed Data (Data Amplification)

DoS: Amplification
DoS: Crash, Exit, or Restart
DoS: Resource Consumption (CPU)
DoS: Resource Consumption (Memory)

Weakness & attack patterns

CWE-409

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /vscode/unpkg/.
Prioritize edge telemetry for network-reachable Eclipse OpenVSX.
Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 4.3 (AV:N)
Sep 14, 2026 · NVD
Initial · CVE published
Sep 14, 2026 · NVD
Added · GHSA-ggqm-q66x-mqh3 published (medium)
Sep 14, 2026 · GitHub Security Advisory
CVE published by MITRE.
Sep 14, 2026 · SOCRadar CTI

References

4 on the record

github.com/eclipse-openvsx/openvsx/pull/2060
Exploit, Third Party Advisory
github.com/eclipse-openvsx/openvsx/security/advisories/GHSA-h685-gqw7-fqw7
Exploit, Third Party Advisory
nvd.nist.gov/vuln/detail/CVE-2026-89321
NVD
github.com/advisories/GHSA-ggqm-q66x-mqh3
Exploit, Third Party Advisory

Elsewhere on this site

Eclipse Foundationevery CVE for this vendor
Unclassifiedsame class
CWE-409other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-89321 is Publishing limits the compressed size of a VSIX (ovsx.publishing.max-content-size, 512 MB by default) but nothing limited how large an…, a medium vulnerability affecting Eclipse OpenVSX from Eclipse Foundation. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-89321. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 4.3 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.