CVE-2026-55096

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Source
https://cve.org/CVERecord?id=CVE-2026-55096
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55096.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-55096
Aliases
  • GHSA-xr72-j7vj-vp7g
Published
2026-09-28T16:38:26Z
Modified
2026-10-21T02:58:36Z
Severity
  • 7.1 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N CVSS Calculator
Summary
SSRF via DNS-resolution gap in _validate_url_security (file download by URL)
Details

fast-mcp-telegram is a Telegram MCP Server. Prior to version 30.1, the send_message/send_message_to_phone MCP tools accept files as a list of http(s) URLs, which the server downloads and attaches to the outgoing Telegram message. Downloads are guarded by _validate_url_security, an SSRF denylist that checks the URL's literal hostname string but never resolves DNS. The fetch (httpx.AsyncClient.get) does its own resolution at request time. Consequently a hostname that resolves to a loopback / private / link-local address passes the guard and is fetched — even with the secure defaults block_private_ips=True and allow_http_urls=False. Because the fetched body is returned to the attacker as a Telegram file attachment, this is a full-read, exfiltrating SSRF, not blind. This issue has been patched in version 30.1.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-184",
        "CWE-918"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55096.json",
    "unresolved_ranges":  [
        {
            "extracted_events":  [
                {
                    "range":  [
                        {
                            "fixed":  "30.1"
                        }
                    ],
                    "source":  "AFFECTED_FIELD",
                    "strategy":  "StringRangeExpression"
                }
            ]
        },
        {
            "extracted_events":  [
                {
                    "range":  [
                        {
                            "fixed":  "30.1"
                        },
                        {
                            "fixed":  "30.1"
                        }
                    ],
                    "source":  "DESCRIPTION"
                }
            ]
        }
    ]
}
References

Affected packages

Git / github.com/leshchenko1979/fast-mcp-telegram

Affected ranges

Type
GIT
Repo
https://github.com/leshchenko1979/fast-mcp-telegram
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
e6b3032cfc906e14f5b84f2c2b8ec378eb457e57
Fixed
efba6fa01232dacb1480bbcfdf1eeb2cf2c09723
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "fixed":  "e6b3032cfc906e14f5b84f2c2b8ec378eb457e57"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "0.30.1",
            "range":  [
                {
                    "fixed":  "efba6fa01232dacb1480bbcfdf1eeb2cf2c09723"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Affected versions

0.*
0.1.0
0.1.1
0.1.2
0.1.3
0.1.4
0.10.0
0.10.1
0.10.2
0.11.0
0.11.1
0.12.1
0.12.2
0.12.3
0.13.0
0.13.1
0.14.0
0.14.1
0.14.2
0.15.0
0.16.0
0.16.1
0.16.2
0.16.3
0.16.5
0.16.6
0.17.0
0.17.1
0.17.2
0.17.3
0.18.0
0.18.1
0.19.0
0.19.1
0.2.0
0.2.1
0.20.0
0.21.0
0.22.0
0.22.1
0.22.2
0.23.1
0.24.0
0.25.0
0.26.0
0.27.0
0.27.1
0.28.0
0.3.0
0.30.0
0.4.0
0.4.1
0.4.2
0.4.3
0.4.4
0.4.5
0.5.0
0.6.0
0.6.1
0.7.0
0.7.1
0.8.0
0.8.1
0.8.2
0.8.3
0.8.4
0.9.0
0.9.1
v0.*
v0.28.2
v0.29.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55096.json"