CVE-2026-93748 kornelski CVE debrief

Who should care

Defenders responsible for maintaining and securing applications that use the http-cache-semantics package should assess their exposure and take necessary actions to prevent exploitation.

Why it matters

CVE-2026-93748 is a high-severity vulnerability in the http-cache-semantics package that allows unauthenticated attackers to retrieve cached responses belonging to other users, potentially leading to unauthorized access to sensitive information. Defenders should prioritize verifying the affected versions of http-cache-semantics in their environment and upgrading to a patched version if necessary.

• attackers can retrieve cached responses belonging to other users, potentially leading to unauthorized access to sensitive information
• defenders need to verify the affected versions of http-cache-semantics in their environment and upgrade to a patched version if necessary
• cache configuration may need to be reviewed and updated to prevent similar vulnerabilities

Technical summary

The http-cache-semantics package fails to properly validate security-zeroed cache entries when processing client max-stale directives, allowing unauthenticated attackers to retrieve cached responses belonging to other users. This vulnerability can be exploited by requesting the same URL with a large max-stale value to obtain another user's Set-Cookie session credentials from shared-cache entries that were deliberately zeroed for security reasons. Defenders should prioritize verifying the affected versions of http-cache-semantics in their environment and upgrading to a patched version if necessary.

Defensive priority

Defenders should prioritize verifying the affected versions of http-cache-semantics in their environment and upgrading to a patched version if necessary.

Recommended defensive actions

• Verify the version of http-cache-semantics in your environment
• Upgrade to a patched version if necessary
• Review and update cache configuration to prevent similar vulnerabilities
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, affected versions, and references to additional information. The http-cache-semantics package through version 4.2.0 is affected, and defenders should verify the affected versions in their environment. The CVE Program record and NIST NVD detail page provide official information on the vulnerability. GitHub issues and repository information may also be relevant.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.