Security readout for executives and security teams
Plain-English summary
Heym before 0.0.21 allowed a logged-in user to run another user's workflow by referencing that workflow's UUID. This could expose workflow outputs and trigger actions the victim did not intend. The issue requires authentication, but the potential confidentiality and integrity impact is high.
Executive priority
Treat as a high-priority upgrade for any shared or production Heym deployment. The risk is not unauthenticated internet takeover, but a logged-in user may access or trigger another user's workflow, creating data exposure and operational side-effect risk.
Technical view
The flaw is CWE-863 authorization bypass in workflow execution. Authenticated attackers could reference victim workflow UUIDs through execute-node or agent subWorkflowId paths, causing Heym to load and execute workflows without proper access validation. CVSS v4.0 is 7.6 high, with low privileges required and no user interaction.
Likely exposure
Exposure is likely limited to organizations running heymrun Heym before version 0.0.21, especially multi-user deployments where workflow UUIDs may be discoverable or leaked. The provided sources do not identify affected hosted services, distributions, or downstream products beyond Heym.
Exploitation context
The source bundle says exploitation requires an authenticated user and knowledge or referenceability of victim workflow UUIDs. CISA KEV is false in the provided data, and no cited source in the bundle states active exploitation in the wild.
Researcher notes
Focus review on workflow-loading authorization boundaries, especially execute nodes and agent subWorkflowId handling. Avoid assuming broader product exposure than Heym before 0.0.21. Public evidence supports a patch, high severity, and authenticated exploitation conditions, but not active exploitation.
Mitigation direction
- Upgrade Heym to version 0.0.21 or later.
- Review the v0.0.21 release notes and patch commit.
- Restrict Heym access to trusted users until upgraded.
- Review vendor guidance for any additional hardening steps.
- Audit workflows for cross-user UUID references before and after upgrade.
Validation and detection
- Inventory deployed Heym versions and identify any below 0.0.21.
- Confirm the patch commit or v0.0.21 release is present.
- Review workflow execution logs for users invoking workflows they do not own.
- Verify authorization checks occur before loading referenced workflow UUIDs.
- Check for unexpected workflow side effects or exposed outputs.
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-863: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-45226 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
- 7.6 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N——VulnCheckCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L1.65.5VulnCheckVulnerability scoring details
Base CVSS 4.0 score
7.6HighVector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/heymrun/heym/releases/tag/v0.0.21CVE reference, VulnCheck · release-notes
- https://github.com/heymrun/heym/pull/93CVE reference, VulnCheck · issue-tracking
- https://github.com/heymrun/heym/commit/3ae3ef6a7d3609da0e910f9ed6b81e99a1661ac8CVE reference, VulnCheck · patch
- https://www.vulncheck.com/advisories/heym-authorization-bypass-in-workflow-executionCVE reference, VulnCheck · third-party-advisory
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.
Incorrect Authorization
Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.