An issue in MongoDB Server's intra-cluster connection setup could allow a party with suitable network access to influence which authentication… (CVE-2026-18691)
A vulnerability in MongoDB Server's intra-cluster connection setup allows an attacker with network access to influence the authentication mechanism used between replica set members. This can lead to the cluster's shared internal credential being transmitted in a less-protected form, potentially exposing it. If the credential is recovered, it could be used to authenticate as the internal superuser on nodes within the deployment.
AI Analysis
Technical Summary
CVE-2026-18691 describes a vulnerability in MongoDB Server where an attacker with suitable network access can manipulate the authentication mechanism during intra-cluster connections between replica set members. This manipulation may cause the cluster's shared internal credential to be sent in a less secure manner, increasing the risk of credential exposure. The exposed credential could then be used to gain superuser authentication on cluster nodes, compromising the deployment's security. The CVSS 3.1 score is 8.8, indicating a critical severity with high impact on confidentiality, integrity, and availability. No patch or remediation details are provided in the available data, and the product is not a cloud service, so remediation status is unknown.
Potential Impact
If exploited, this vulnerability could allow an attacker to recover the cluster's internal superuser credential, enabling unauthorized authentication to MongoDB nodes. This compromises the confidentiality, integrity, and availability of the database cluster, potentially allowing full control over the deployment.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or temporary workaround is provided in the available data, users should monitor vendor communications for updates. Network-level controls restricting access to intra-cluster communication channels may reduce exposure risk.
An issue in MongoDB Server's intra-cluster connection setup could allow a party with suitable network access to influence which authentication… (CVE-2026-18691)
Description
A vulnerability in MongoDB Server's intra-cluster connection setup allows an attacker with network access to influence the authentication mechanism used between replica set members. This can lead to the cluster's shared internal credential being transmitted in a less-protected form, potentially exposing it. If the credential is recovered, it could be used to authenticate as the internal superuser on nodes within the deployment.
CVSS v3.1
Score 8.8high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-18691 describes a vulnerability in MongoDB Server where an attacker with suitable network access can manipulate the authentication mechanism during intra-cluster connections between replica set members. This manipulation may cause the cluster's shared internal credential to be sent in a less secure manner, increasing the risk of credential exposure. The exposed credential could then be used to gain superuser authentication on cluster nodes, compromising the deployment's security. The CVSS 3.1 score is 8.8, indicating a critical severity with high impact on confidentiality, integrity, and availability. No patch or remediation details are provided in the available data, and the product is not a cloud service, so remediation status is unknown.
Potential Impact
If exploited, this vulnerability could allow an attacker to recover the cluster's internal superuser credential, enabling unauthorized authentication to MongoDB nodes. This compromises the confidentiality, integrity, and availability of the database cluster, potentially allowing full control over the deployment.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or temporary workaround is provided in the available data, users should monitor vendor communications for updates. Network-level controls restricting access to intra-cluster communication channels may reduce exposure risk.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-jx4v-jf9c-3rh7
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-18691"]
- Ecosystems
- []
- Database Specific Severity
- CRITICAL
- Cvss Version
- 3.1
Threat ID: 6a7c9b72bf8831d539ce06b7
Added to database: 08/12/2026, 16:12:34 UTC
Last enriched: 08/12/2026, 17:27:55 UTC
Last updated: 08/12/2026, 17:41:00 UTC
Views: 2
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.