dbcve.org
Race ConditionWeakness · CWE-362

CVE-2026-40943

HIGH · 8.7 CVSS v4.0 Published 2026-04-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
96/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Oxia is a metadata store and coordination system. Prior to 0.16.2, a race condition between session heartbeat processing and session closure can cause the server to panic with send on closed channel. The heartbeat() method uses a blocking channel send while holding a mutex, and under specific timing with concurrent close() calls, this can lead to either a deadlock (channel buffer full) or a panic (send on closed channel after TOCTOU gap in KeepAlive). This vulnerability is fixed in 0.16.2.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Oxia metadata store has a race condition in session handling where the heartbeat() method performs a blocking channel send while holding a mutex. Concurrent close() calls can trigger either a deadlock (channel buffer full) or a panic due to send on closed channel after a TOCTOU gap in KeepAlive, causing server denial of service.

MitigationUpgrade Oxia to version 0.16.2 or later to receive the patched session heartbeat and closure synchronization logic.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Oxia installation and version
    Run 'oxia version' command or check the installed Oxia binary/package version file to obtain the exact version number
    Affected if Version is earlier than 0.16.2
  2. Confirm metadata store session handling is active
    Review Oxia configuration files for session and heartbeat settings. Check if the metadata store is accepting client connections and has session management enabled
    Affected if Session handling and heartbeat mechanisms are configured and actively in use
  3. Examine logs for session-related panics
    Search server logs for panic messages containing 'send on closed channel' or deadlock indicators related to session/heartbeat operations
    Affected if Recent logs show channel-related panics in session handling code or unexpected server hangs during session operations
  4. Monitor for concurrent session close and heartbeat activity
    Review application traffic or audit logs for patterns where multiple session close operations occur simultaneously with heartbeat activity, which could trigger the race condition
    Affected if Concurrent session management operations are occurring alongside active heartbeat mechanisms

The environment is affected if Oxia version is below 0.16.2 AND the metadata store session handling with heartbeat functionality is enabled and in use

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Oxia to version 0.16.2 or later to receive the patched session heartbeat and closure synchronization logic.

Recommended fix High confidence

Oxia version 0.16.2

  1. 1. Identify the currently running Oxia version using the server's version flag or startup logs
  2. 2. Review release notes for Oxia version 0.16.2 to understand changes and confirm the fix addresses the race condition vulnerability
  3. 3. Plan maintenance window for the upgrade, as session disruption may occur
  4. 4. Update Oxia deployment to version 0.16.2 using the project's standard upgrade procedure (e.g., package manager, container image update, or binary replacement)
  5. 5. Restart Oxia services to load the new version
  6. 6. Verify the upgrade was successful by checking the running version
  7. 7. Monitor system logs for any panics or errors related to session heartbeat or closure to confirm the vulnerability is resolved
Caveat Review release notes for version 0.16.2; minor version updates typically have low risk but check for configuration or API changes

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40943 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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