Security readout for executives and security teams
Plain-English summary
This is a denial-of-service flaw in Oracle MySQL Server. A highly privileged user who can reach MySQL over the network could make the server hang or crash repeatedly. It does not indicate data theft or tampering, but it can disrupt applications that depend on affected MySQL instances.
Executive priority
Treat this as a reliability risk for business applications backed by MySQL, especially where many users or services depend on one database. Prioritize patching exposed or critical instances, but the high privilege requirement makes it less urgent than unauthenticated remote code execution issues.
Technical view
CVE-2021-35627 affects MySQL Server Optimizer in supported versions 8.0.26 and prior. Oracle rates it CVSS 3.1 4.9: AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H. The impact is availability only: complete denial of service through hang or repeatable crash.
Likely exposure
Exposure is mainly MySQL Server 8.0.26 and prior, including deployments reachable over MySQL network protocols by privileged database users. Internet exposure is less important than credential exposure because the attacker needs high privileges. Check appliances or products that bundle MySQL, since NetApp published a related advisory.
Exploitation context
The provided sources do not report active exploitation, and KEV status is false. The vulnerability is described as easily exploitable after a high-privileged attacker has network access via multiple protocols. Expected abuse is service disruption, not confidentiality or integrity compromise.
Researcher notes
The key constraint is PR:H: validation should focus on version, privilege boundaries, and network reachability rather than public exploitability. Sources identify the vulnerable component and availability impact, but do not provide detailed root cause, exploit indicators, or a specific fixed version in the supplied bundle.
Mitigation direction
- Review Oracle's October 2021 Critical Patch Update for the applicable MySQL Server fix.
- Upgrade affected MySQL Server instances beyond 8.0.26 where vendor guidance applies.
- Restrict network access to MySQL services to trusted hosts and administration paths.
- Review privileged MySQL accounts and remove unnecessary elevated access.
- Check NetApp guidance if using NetApp products that may include affected MySQL components.
Validation and detection
- Inventory MySQL Server versions and flag 8.0.26 and prior.
- Confirm whether MySQL network access is limited to trusted systems.
- Review privileged database accounts with remote access capability.
- Check maintenance records for Oracle October 2021 CPU or later MySQL updates.
- Review monitoring for unexplained MySQL hangs, crashes, or repeated restarts.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-35627 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H1.23.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.9MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.oracle.com/security-alerts/cpuoct2021.htmlCVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20211022-0003/CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.