Security readout for executives and security teams
Plain-English summary
CVE-2020-36320 is a denial-of-service risk in Vaadin 7 email validation. A malicious email address can trigger excessive CPU work, potentially making an affected application slow or unavailable. It affects Vaadin 7.0.0 through 7.7.21, specifically com.vaadin:vaadin-server.
Executive priority
Treat this as a high-priority availability issue for internet-facing Vaadin 7 applications. It does not indicate data theft, but a simple unauthenticated request pattern may degrade service if affected validation paths are exposed.
Technical view
The issue is an unsafe regular expression in Vaadin 7 EmailValidator. Network attackers need no authentication or user interaction if they can submit email input that reaches this validator. Impact is availability only, rated CVSS 3.1 7.5 with CWE-400 uncontrolled resource consumption.
Likely exposure
Exposure is most likely in Java web applications using com.vaadin:vaadin-server versions 7.0.0 through 7.7.21 and validating attacker-controlled email fields with Vaadin's EmailValidator.
Exploitation context
The provided sources do not show known active exploitation, and the CVE is not listed as KEV. The attack path is plausible for public forms or APIs because the CVSS vector is network-accessible, low-complexity, unauthenticated, and requires no user interaction.
Researcher notes
Evidence supports ReDoS in EmailValidator for Vaadin 7.0.0 through 7.7.21. The bundle includes an issue and pull request, but no exploit-in-the-wild evidence or detailed fixed-version statement beyond the affected range. Validate exposure by dependency version and reachable validator usage.
Mitigation direction
- Inventory applications using com.vaadin:vaadin-server or Vaadin 7.
- Confirm whether deployed versions are 7.0.0 through 7.7.21.
- Follow Vaadin's advisory for upgrade or remediation guidance.
- Prioritize public forms and APIs accepting email addresses.
- Apply rate limiting to exposed email submission paths where feasible.
Validation and detection
- Check dependency manifests, lockfiles, and SBOMs for com.vaadin:vaadin-server.
- Identify code paths using Vaadin EmailValidator with untrusted input.
- Confirm deployed Vaadin versions are not in the affected range.
- Review application telemetry for slow or repeated email validation requests.
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.
CWE-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-36320 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://vaadin.com/security/cve-2020-36320CVE reference · x_refsource_MISC
- https://github.com/vaadin/framework/issues/7757CVE reference · x_refsource_MISC
- https://github.com/vaadin/framework/pull/12104CVE reference · x_refsource_MISC
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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.