Cursor: recover the workstation and review credentials

What the vendor investigation confirms

In its November 13 update, Cursor attributes the sequence to a key exposed by Fireworks: historical data contained credentials used to reach SaaS tools and subsequently tamper with the extension cache. The incident involves Anthropic.claude-code versions 2.1.312 and 2.1.313 on October 29. The company says its applications, official updates and customer repositories were unaffected. These are vendor findings; teams need to examine their own environment.

Build a workstation investigation queue

Assign an owner to assemble installation records, user identities and the period under examination. Preserve where each observation came from and distinguish a version present today from an installation recorded during the investigated window. A package missing from current inventory leaves a historical question open. Use official communications addressed to your organization to scope the review.

For each selected workstation, open a record covering authorized collection, observed indicators and telemetry limitations. Agree with the manager how the developer will work while analysis continues. A managed alternative prepared beforehand can reduce pressure to release a machine whose condition remains uncertain. Document who receives cases without sufficient evidence.

Make recovery a workstation decision

The October 29 notice, updated October 30, advises searching for published indicators, isolating hosts with evidence, removing persistence and assessing rebuilding. It also recommends rotating accessible credentials and sessions from a trusted system. Cursor warns that uninstalling the extension alone may be insufficient.

Turn that guidance into an approved organizational procedure. Before removing artifacts, define the preservation needed for investigation and who authorizes intervention. Record execution, subsequent checks and outstanding issues handed to the workstation owner. Consult current indicators and instructions in the official notice; a list copied into a ticket can lose context or become outdated.

Decide what happens to each reviewed credential

In a separate exercise, use a synthetic account to represent a development tool accessing an internal service. Identify the issuer, application owner and administrator able to revoke access. Record permitted identifiers and timestamps without including secret values in reports. This rehearsal evaluates the team's procedure and does not reproduce the attack described by the vendor.

Revoke the test credential at its issuer and observe an authorized request that was previously accepted. Then validate its replacement with the minimum access approved by the owner. Retain both outcomes and investigate integrations that continue operating without explanation. For real credentials under investigation, coordinate preservation, dependencies and urgency with incident response, avoiding service interruption through a change that has no accountable owner.

Authorize a return with explicit conditions

Bring the workstation decision and access review together in one return record. The technical owner should explain which checks ran, which evidence supports the conclusion and which questions depend on third parties. The service manager accepts the bounded use, records exceptions and schedules their review.

After the exercise, review how your organization approves extensions and retains installation records. Choose one observable improvement, assign an owner and test it with a small team before expanding. This governance proposal complements vendor instructions. It is not an independent forensic investigation of the incident, and a conclusion about one workstation cannot establish the condition of every other device in the organization.

Frequently asked questions

Related reading

• Fireworks and Notion: scope data at a provider
• OpenCode Console: prove provider key revocation
• MCP: compare dependencies across restarts

Sources and references

• Cursor: investigation published November 13
• Cursor: October 29 notice, updated October 30

Original Pentesty analysis, published November 14, 2026. The proposed scenarios are editorial guidance, with scope and validation to be defined for each environment.