Heym before 0.0.53 Slack Webhook Signature Verification Bypass

Heym before 0.0.53 fails to verify Slack request signatures when trigger nodes lack credential IDs or have empty signing secrets. Remote unauthenticated attackers can send forged Slack events to known webhook URLs to trigger workflows with the owner's credentials.

Problem type

Improper Authentication

Affected products

heymrun

heym

< 0.0.53 - AFFECTED

0.0.53 - UNAFFECTED

References

GitHub Security Advisory (GHSA-pm6h-x3h5-j38h)

https://github.com/heymrun/heym/security/advisories/GHSA-pm6h-x3h5-j38h

vendor-advisory

Patch Commit

https://github.com/heymrun/heym/commit/341d1012367cd74f85c617e1c98dd49e3fcb5e83

patch

VulnCheck Advisory: Heym before 0.0.53 Slack Webhook Signature Verification Bypass

https://www.vulncheck.com/advisories/heym-before-0.0.53-slack-webhook-signature-verification-bypass

third-party-advisory

JSON source

https://cveawg.mitre.org/api/cve/CVE-2026-101049

Click to expand

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-101049",
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "dateUpdated": "2026-09-27T16:33:42.372Z",
    "dateReserved": "2026-09-27T15:48:49.472Z",
    "datePublished": "2026-09-27T16:28:28.128Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck",
        "dateUpdated": "2026-09-27T16:33:42.372Z"
      },
      "datePublic": "2026-06-26T00:00:00.000Z",
      "title": "Heym before 0.0.53 Slack Webhook Signature Verification Bypass",
      "descriptions": [
        {
          "lang": "en",
          "value": "Heym before 0.0.53 fails to verify Slack request signatures when trigger nodes lack credential IDs or have empty signing secrets. Remote unauthenticated attackers can send forged Slack events to known webhook URLs to trigger workflows with the owner's credentials."
        }
      ],
      "affected": [
        {
          "vendor": "heymrun",
          "product": "heym",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "0.0.53"
            },
            {
              "version": "0.0.53",
              "status": "unaffected",
              "versionType": "semver"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "Improper Authentication",
              "cweId": "CWE-287",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://github.com/heymrun/heym/security/advisories/GHSA-pm6h-x3h5-j38h",
          "name": "GitHub Security Advisory (GHSA-pm6h-x3h5-j38h)",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://github.com/heymrun/heym/commit/341d1012367cd74f85c617e1c98dd49e3fcb5e83",
          "name": "Patch Commit",
          "tags": [
            "patch"
          ]
        },
        {
          "url": "https://www.vulncheck.com/advisories/heym-before-0.0.53-slack-webhook-signature-verification-bypass",
          "name": "VulnCheck Advisory: Heym before 0.0.53 Slack Webhook Signature Verification Bypass",
          "tags": [
            "third-party-advisory"
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS"
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N",
            "attackVector": "NETWORK",
            "attackComplexity": "HIGH",
            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "UNCHANGED",
            "confidentialityImpact": "LOW",
            "integrityImpact": "HIGH",
            "availabilityImpact": "NONE",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM"
          }
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "okcomputerfan",
          "type": "finder"
        },
        {
          "lang": "en",
          "value": "mbakgun",
          "type": "remediation developer"
        }
      ]
    }
  }
}