FKIE_CVE-2026-113799

Vulnerability from fkie_nvd - Published: 2026-10-21 17:18 - Updated: 2026-10-22 17:40
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
Summary
Slack Morphism is a client library for Slack Web/Events API/Socket Mode and Block Kit. Versions 1.0.0 through 2.27.0 expose the correct Slack request HMAC when signature verification fails. For an invalid request, `slack-morphism` computes the correct signature for the attacker-controlled timestamp and request body and stores it in `SlackEventWrongSignatureError.generated_hash`. The error's `Debug` and `Display` representations expose that value, and the default Axum listener error handler logs it at error level. An attacker who can both reach the application's Slack callback endpoint and read its application/service logs can therefore use the verifier as a chosen-message HMAC oracle. The attacker can send an arbitrary request with an invalid signature, recover the correct signature from the resulting log entry, and resend the same request within the five-minute freshness window. The second request passes Slack Morphism's signature verification and reaches the protected application callback without the attacker knowing the Slack signing secret. Version 2.28.0 patches the issue.
References
security-advisories@github.comhttps://github.com/abdolence/slack-morphism-rust/commit/ac95d0d4539d0eac548a8db99c51c0c1ae832756
security-advisories@github.comhttps://github.com/abdolence/slack-morphism-rust/pull/387
security-advisories@github.comhttps://github.com/abdolence/slack-morphism-rust/releases/tag/v2.28.0
security-advisories@github.comhttps://github.com/abdolence/slack-morphism-rust/security/advisories/GHSA-26w4-8w32-4x3v
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "slack-morphism-rust",
          "vendor": "abdolence",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.0.0, \u003c 2.28.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Slack Morphism is a client library for Slack Web/Events API/Socket Mode and Block Kit. Versions 1.0.0 through 2.27.0 expose the correct Slack request HMAC when signature verification fails. For an invalid request, `slack-morphism` computes the correct signature for the attacker-controlled timestamp and request body and stores it in `SlackEventWrongSignatureError.generated_hash`. The error\u0027s `Debug` and `Display` representations expose that value, and the default Axum listener error handler logs it at error level. An attacker who can both reach the application\u0027s Slack callback endpoint and read its application/service logs can therefore use the verifier as a chosen-message HMAC oracle. The attacker can send an arbitrary request with an invalid signature, recover the correct signature from the resulting log entry, and resend the same request within the five-minute freshness window. The second request passes Slack Morphism\u0027s signature verification and reaches the protected application callback without the attacker knowing the Slack signing secret. Version 2.28.0 patches the issue."
    }
  ],
  "id": "CVE-2026-113799",
  "lastModified": "2026-10-22T17:40:46.877",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-21T17:18:25.123",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/abdolence/slack-morphism-rust/commit/ac95d0d4539d0eac548a8db99c51c0c1ae832756"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/abdolence/slack-morphism-rust/pull/387"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/abdolence/slack-morphism-rust/releases/tag/v2.28.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/abdolence/slack-morphism-rust/security/advisories/GHSA-26w4-8w32-4x3v"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-532"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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