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Fencer Intel
high 7.5

CVE-2025-21521 json

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Thread Pooling).

published last yr. modified 4mo ago also EUVD-2025-2510

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Thread Pooling). Supported versions that are affected are 8.0.39 and prior, 8.4.2 and prior and 9.0.1 and prior. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. 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).

Patch / fix

  • oracle mysql 8.0.40, 8.4.3, 9.1.0
  • oracle mysql_server 8.0.40, 8.4.3, 9.1.0
  • mysql-8.0 Ubuntu 20.04 LTS 8.0.40-0ubuntu0.20.04.1
  • mysql-8.0 Ubuntu 22.04 LTS 8.0.40-0ubuntu0.22.04.1
  • mysql-8.0 Ubuntu 24.04 LTS 8.0.40-0ubuntu0.24.04.1

ubuntu advisories UBUNTU-CVE-2025-21521

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • mysql8.4 RHEL 10.0 8.4.4-2.el10
  • mysql8.4-libs RHEL 10.0 8.4.4-2.el10
  • mysql8.4-test RHEL 10.0 8.4.4-2.el10
  • mysql8.4-common RHEL 10.0 8.4.4-2.el10
  • mysql8.4-errmsg RHEL 10.0 8.4.4-2.el10
  • mysql8.4-server RHEL 10.0 8.4.4-2.el10
  • mysql8.4-test-data RHEL 10.0 8.4.4-2.el10
  • mysql RHEL 9 8.0.41-2.el9_5

red hat advisories RHBA-2025:5321RHSA-2025:2883RHSA-2025:2882RHSA-2025:1767RHSA-2025:1766RHSA-2025:1757

  • mysql AlmaLinux 9 8.0.41-2.el9_5
  • mysql-libs AlmaLinux 9 8.0.41-2.el9_5
  • mysql-test AlmaLinux 9 8.0.41-2.el9_5
  • mysql-common AlmaLinux 9 8.0.41-2.el9_5
  • mysql-errmsg AlmaLinux 9 8.0.41-2.el9_5
  • mysql-server AlmaLinux 9 8.0.41-2.el9_5
  • mecab AlmaLinux 8 0.996-2.module_el8.10.0+3965+b415b607
  • mecab AlmaLinux 8 0.996-2.module_el8.6.0+3340+d764b636

almalinux advisories ALSA-2025:1671ALSA-2025:1673

  • mysql Rocky Linux 9 8.0.41-2.el9_5
  • mecab Rocky Linux 8 0.996-2.module+el8.10.0+1676+9b4b6e24
  • mysql Rocky Linux 8 8.0.41-1.module+el8.10.0+1937+28fbbc83.0.1
  • mecab-ipadic Rocky Linux 8 2.7.0.20070801-17.module+el8.10.0+1937+28fbbc83

rocky linux advisories RLSA-2025:1671RLSA-2025:1673

  • mysql Azure Linux 3.0 8.0.40-1

azure linux advisories AZL-63039

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-21521 updated cvss 7.5

mysql: MySQL Server: Denial of service in Thread Pooling component

  • Red Hat CodeReady Linux Builder (v. 9) mysql-libs 8.0.41-2.el9_5, mysql-test 8.0.41-2.el9_5
    fixed: vendor fix RHSA-2025:1671
  • Red Hat CodeReady Linux Builder EUS (v.9.2) mysql-libs 8.0.40-1.el9_2.1, mysql-test 8.0.40-1.el9_2.1
    fixed: vendor fix RHSA-2025:1767
  • Red Hat CodeReady Linux Builder EUS (v.9.4) mysql-libs 8.0.40-1.el9_4, mysql-test 8.0.40-1.el9_4
    fixed: vendor fix RHSA-2025:1756
  • Red Hat Enterprise Linux AppStream (v. 8) mecab 0.996-2.module+el8.10.0+22857+7f331edd, mysql 8.0.41-1.module+el8.10.0+22857+7f331edd, mysql-libs 8.0.41-1.module+el8.10.0+22857+7f331edd, mysql-test 8.0.41-1.module+el8.10.0+22857+7f331edd, mysql-common 8.0.41-1.module+el8.10.0+22857+7f331edd, mysql-errmsg 8.0.41-1.module+el8.10.0+22857+7f331edd, +3 more
    fixed: vendor fix RHSA-2025:1673
  • Red Hat Enterprise Linux AppStream (v. 9) mysql 8.0.41-2.el9_5, mysql-common 8.0.41-2.el9_5, mysql-errmsg 8.0.41-2.el9_5, mysql-server 8.0.41-2.el9_5
    fixed: vendor fix RHSA-2025:1671
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) mecab 0.996-1.module+el8.0.0+3898+e09bb8de.9, mysql 8.0.40-1.module+el8.2.0+22898+0bdd8c5b.4, mysql-libs 8.0.40-1.module+el8.2.0+22898+0bdd8c5b.4, mysql-test 8.0.40-1.module+el8.2.0+22898+0bdd8c5b.4, mysql-common 8.0.40-1.module+el8.2.0+22898+0bdd8c5b.4, mysql-errmsg 8.0.40-1.module+el8.2.0+22898+0bdd8c5b.4, +3 more
    fixed: vendor fix RHSA-2025:2883
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) mecab 0.996-1.module+el8.0.0+3898+e09bb8de.9, mysql 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-libs 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-test 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-common 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-errmsg 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, +3 more
    fixed: vendor fix RHSA-2025:2882
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) mecab 0.996-2.module+el8.6.0+16523+5cb0e868, mysql 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-libs 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-test 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-common 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-errmsg 8.0.40-1.module+el8.6.0+22864+ceaef991, +3 more
    fixed: vendor fix RHSA-2025:1766
show 9 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) mecab 0.996-1.module+el8.0.0+3898+e09bb8de.9, mysql 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-libs 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-test 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-common 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-errmsg 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, +3 more
    fixed: vendor fix RHSA-2025:2882
  • Red Hat Enterprise Linux AppStream E4S (v.8.6) mecab 0.996-2.module+el8.6.0+16523+5cb0e868, mysql 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-libs 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-test 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-common 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-errmsg 8.0.40-1.module+el8.6.0+22864+ceaef991, +3 more
    fixed: vendor fix RHSA-2025:1766
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) mysql 8.0.40-2.el9_0, mysql-common 8.0.40-2.el9_0, mysql-errmsg 8.0.40-2.el9_0, mysql-server 8.0.40-2.el9_0
    fixed: vendor fix RHSA-2025:1755
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) mecab 0.996-2.module+el8.8.0+18436+8918dd75, mysql 8.0.40-1.module+el8.8.0+22863+a1071e1e, mysql-libs 8.0.40-1.module+el8.8.0+22863+a1071e1e, mysql-test 8.0.40-1.module+el8.8.0+22863+a1071e1e, mysql-common 8.0.40-1.module+el8.8.0+22863+a1071e1e, mysql-errmsg 8.0.40-1.module+el8.8.0+22863+a1071e1e, +3 more
    fixed: vendor fix RHSA-2025:1757
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) mysql 8.0.40-1.el9_2.1, mysql-common 8.0.40-1.el9_2.1, mysql-errmsg 8.0.40-1.el9_2.1, mysql-server 8.0.40-1.el9_2.1
    fixed: vendor fix RHSA-2025:1767
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) mysql 8.0.40-1.el9_4, mysql-common 8.0.40-1.el9_4, mysql-errmsg 8.0.40-1.el9_4, mysql-server 8.0.40-1.el9_4
    fixed: vendor fix RHSA-2025:1756
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) mecab 0.996-1.module+el8.0.0+3898+e09bb8de.9, mysql 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-libs 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-test 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-common 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, mysql-errmsg 8.0.40-1.module+el8.4.0+22899+4f2ca788.1, +3 more
    fixed: vendor fix RHSA-2025:2882
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) mecab 0.996-2.module+el8.6.0+16523+5cb0e868, mysql 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-libs 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-test 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-common 8.0.40-1.module+el8.6.0+22864+ceaef991, mysql-errmsg 8.0.40-1.module+el8.6.0+22864+ceaef991, +3 more
    fixed: vendor fix RHSA-2025:1766
  • Red Hat Enterprise Linux 6 mysql, mysql-libs, mysql-test, mysql-bench, mysql-server, mysql-embedded Red Hat Enterprise Linux 10 mysql8.4
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

1.10% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Oracle Corporation MySQL Server

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.