Vulnerability-Lookup

CVE-2026-81099 (GCVE-0-2026-81099)

Vulnerability from cvelistv5 – Published: 2026-08-27 14:50 – Updated: 2026-08-29 11:48

Title

Timescale tiger-slack DNS Rebinding via Disabled Host Header Allow-List

Summary

tiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. mcp/src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, and a page in a browser could point a name it controlled at the address the server was bound to and drive the locally reachable Slack MCP server through the visitor's browser. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository publishes no release that brackets the fix, so the affected boundary is the commit preceding it.

Severity

7.6 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

6.8 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-27 17:53 UTC

CWE

CWE-346 - Origin Validation Error

Assigner

VulnCheck mitre root

References

3 references

URL	Tags
https://github.com/timescale/tiger-slack	product
https://github.com/timescale/tiger-slack/pull/146	issue-trackingpatch
https://www.vulncheck.com/advisories/timescale-ti…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
timescale	tiger-slack	Unaffected: 23faf7ee7e7f73e5ea4f67e627c1aca94bba1f09 (git) Affected: 0 , < 23faf7ee7e7f73e5ea4f67e627c1aca94bba1f09 (git)	guessed

Date Public

2026-08-26 00:00

Credits

Avishai Gonen (Pluto Security)

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-81099

Vulnerability from fkie_nvd - Published: 2026-08-27 17:20 - Updated: 2026-08-27 20:18

Severity

6.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	disclosure@vulncheck.com	https://github.com/timescale/tiger-slack
	disclosure@vulncheck.com	https://github.com/timescale/tiger-slack/pull/146
	disclosure@vulncheck.com	https://www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-host-header-allow-list

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/timescale/tiger-slack/pull/146"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-host-header-allow-list"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-346"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}

GHSA-P943-9HP2-H27Q

Vulnerability from github – Published: 2026-08-27 18:32 – Updated: 2026-08-27 18:32

Details

Severity

6.8 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

7.6 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-81099"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-346"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-27T17:20:52Z",
    "severity": "HIGH"
  },
  "details": "tiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. mcp/src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, and a page in a browser could point a name it controlled at the address the server was bound to and drive the locally reachable Slack MCP server through the visitor\u0027s browser. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository publishes no release that brackets the fix, so the affected boundary is the commit preceding it.",
  "id": "GHSA-p943-9hp2-h27q",
  "modified": "2026-08-27T18:32:26Z",
  "published": "2026-08-27T18:32:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81099"
    },
    {
      "type": "WEB",
      "url": "https://github.com/timescale/tiger-slack/pull/146"
    },
    {
      "type": "WEB",
      "url": "https://github.com/timescale/tiger-slack"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-host-header-allow-list"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-81099 (GCVE-0-2026-81099)

FKIE_CVE-2026-81099

GHSA-P943-9HP2-H27Q

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