high CVSS 7.5 EPSS 0.47%

CVE-2026-46863·MySQL vulnerability

Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Connection Handling). Supported versions that are affected are MySQL Server: 8.4.0-8.4.9, 9.0.0-9.7.0; MySQL Cluster: 8.0.11-8.0.46, 8.4.0-8.4.9 and 9.0.0-9.7.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise MySQL Server, MySQL Cluster. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server, MySQL Cluster. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Severity
high
Software
MySQL
Fixed in
8.0.46-0ubuntu0.20.04.1+esm3
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 0.47% — higher than 37% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2026-46863 scores 7.5 on CVSS, so a successful attack would be serious — but at 0.47%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 9.0.0

Until: 9.7.0

Fixed in: 8.0.46-0ubuntu0.20.04.1+esm3

How to fix this CVE

CVE-2026-46863 is a connection handling vulnerability in MySQL that allows unauthenticated attackers to trigger a denial-of-service condition, causing the database server to hang or crash repeatedly. Upgrade MySQL Server immediately to version 8.0.46 or later, or apply the patched version recommended by your Linux distribution. This vulnerability requires network access but no authentication, making it a critical availability risk for exposed MySQL instances.

sudo dnf update mysql-server

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

Repeated TCP connection attempts followed by immediate RST (connection reset) packets on port 3306; MySQL error log entries showing 'Lost connection to MySQL server during query' or 'MySQL server has gone away' occurring at regular intervals or in rapid succession

How to check if you are affected

  1. Check your MySQL version: mysql --version or SELECT VERSION(); from within a MySQL client session
  2. Identify if your MySQL instance is exposed to the network: netstat -tlnp | grep mysql or ss -tlnp | grep mysql to confirm port 3306 is listening on 0.0.0.0 or a public interface
  3. Review MySQL error logs for repeated connection failures or server crashes: tail -f /var/log/mysql/error.log and look for patterns of abrupt shutdowns or connection rejections
  4. Verify the patch was applied by confirming the version is 8.0.46 or later: mysql --version and cross-check against your package manager: apt show mysql-server or dnf info mysql-server

FAQ

What is CVE-2026-46863?

CVE-2026-46863 is a vulnerability in MySQL's connection handling that permits unauthenticated remote attackers to crash or hang the database server, resulting in a complete denial-of-service condition without requiring authentication credentials.

Is CVE-2026-46863 being actively exploited?

No, this vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and no public exploit code is available at this time.

What versions of MySQL are affected by CVE-2026-46863?

MySQL Server versions 8.4.0 through 8.4.9, 9.0.0 through 9.7.0, and MySQL Cluster versions 8.0.11 through 8.0.46, 8.4.0 through 8.4.9, and 9.0.0 through 9.7.0 are vulnerable.

How do I check if my server is vulnerable to CVE-2026-46863?

Run 'mysql --version' to determine your installed version, then compare it against the affected ranges listed above; vulnerable systems will show versions 8.4.0-8.4.9 or 9.0.0-9.7.0.

Does Defensia detect CVE-2026-46863?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If MySQL is installed on a monitored server, CVE-2026-46863 will appear in your dashboard with remediation steps.

Related MySQL CVEs

CVE-2026-29080CVSS 8.8A SQL injection vulnerability in `FilterEngine.create_sqla_query()` allows any authenticated Rucio user to execute arbitrary SQL against the backend database through the DID search endpoint (`GET /dids/<scope>/dids/search`). On Oracle deployments attacker-controlled filter keys and values are interpolated directly into `sqlalchemy.text()` via Python `.format()`, completely bypassing parameterization. This enables full database compromise including extraction of authentication tokens, password hashes, and all managed data identifiers. This affects versions 1.27.0 and later before 35.8.5, 38.5.5, 39.4.2, and 40.1.1. The vulnerability exists in `lib/rucio/core/did_meta_plugins/filter_engine.py` within the `create_sqla_query()` method. When the database dialect is Oracle, filter expressions for JSON metadata columns are constructed using `text()` with Python string formatting. Both `key` and `value` are attacker-controlled strings derived from HTTP query parameters. The `text()` function creates a raw SQL fragment — it does **not** escape or parameterize its contents. Any authenticated Rucio user can exploit this through the DID search API to execute arbitrary SQL against the backend database. This can expose all managed data identifiers and sensitive tables such as identities, tokens, accounts, rse_settings, and rules, and may allow modification of database contents. The issue affects Oracle deployments using the default json_meta plugin and does not affect PostgreSQL or MySQL deployments using that plugin. This vulnerability has been fixed in versions 35.8.5, 38.5.5, 39.4.2, and 40.1.1.
CVE-2026-60163CVSS 8.4Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Group Replication Plugin). Supported versions that are affected are MySQL Server: 8.4.0-8.4.10, 9.7.0-9.7.1; MySQL Cluster: 8.0.0-8.0.47, 8.4.0-8.4.10 and 9.7.0-9.7.1. Easily exploitable vulnerability allows unauthenticated attacker with logon to the infrastructure where MySQL Server, MySQL Cluster executes to compromise MySQL Server, MySQL Cluster. Successful attacks of this vulnerability can result in takeover of MySQL Server, MySQL Cluster. CVSS 3.1 Base Score 8.4 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
CVE-2026-60315CVSS 8.2Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: X Plugin). Supported versions that are affected are MySQL Server: 8.4.0-8.4.10, 9.7.0-9.7.1; MySQL Cluster: 8.0.0-8.0.47, 8.4.0-8.4.10 and 9.7.0-9.7.1. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise MySQL Server, MySQL Cluster. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server, MySQL Cluster and unauthorized read access to a subset of MySQL Server, MySQL Cluster accessible data. CVSS 3.1 Base Score 8.2 (Confidentiality and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H).
CVE-2026-46862CVSS 7.5Vulnerability in the MySQL Router product of Oracle MySQL (component: Router: General). Supported versions that are affected are 8.4.0-8.4.9 and 9.0.0-9.7.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via TLS to compromise MySQL Router. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Router. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
CVE-2026-60316CVSS 7.2Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: X Plugin). Supported versions that are affected are MySQL Server: 8.4.0-8.4.10, 9.7.0-9.7.1; MySQL Cluster: 8.0.0-8.0.47, 8.4.0-8.4.10 and 9.7.0-9.7.1. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server, MySQL Cluster. Successful attacks of this vulnerability can result in takeover of MySQL Server, MySQL Cluster. CVSS 3.1 Base Score 7.2 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H).

References

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