Vulnerability-Lookup

CVE-2026-54638 (GCVE-0-2026-54638)

Vulnerability from cvelistv5 – Published: 2026-07-28 22:14 – Updated: 2026-07-28 22:14

Title

td has pre-auth denial of service via unbounded memory allocation in proto.UnencryptedMessage.Decode

Summary

gotd/td is a T Telegram MTProto API client in Go. Prior to 0.145.1, proto.UnencryptedMessage.Decode in proto/unencrypted_message.go read attacker controlled dataLen from an unauthenticated MTProto unencrypted packet and allocated make([]byte, dataLen) before checking the remaining buffer, allowing remote unauthenticated denial of service through excessive memory allocation and CPU or garbage collection pressure. This issue is fixed in version 0.145.1.

Severity

7.5 (High)


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

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling
CWE-789 - Memory Allocation with Excessive Size Value

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/gotd/td/security/advisories/GH…	x_refsource_CONFIRM
https://github.com/gotd/td/issues/1711	x_refsource_MISC
https://github.com/gotd/td/commit/9d5d1f31ea5022d…	x_refsource_MISC
https://github.com/gotd/td/releases/tag/v0.145.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
gotd	td	Affected: < 0.145.1

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "td",
          "vendor": "gotd",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.145.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "gotd/td is a T Telegram MTProto API client in Go. Prior to 0.145.1, proto.UnencryptedMessage.Decode in proto/unencrypted_message.go read attacker controlled dataLen from an unauthenticated MTProto unencrypted packet and allocated make([]byte, dataLen) before checking the remaining buffer, allowing remote unauthenticated denial of service through excessive memory allocation and CPU or garbage collection pressure. This issue is fixed in version 0.145.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-789",
              "description": "CWE-789: Memory Allocation with Excessive Size Value",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-28T22:14:53.550Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/gotd/td/security/advisories/GHSA-whmm-qj9r-wvr2",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/gotd/td/security/advisories/GHSA-whmm-qj9r-wvr2"
        },
        {
          "name": "https://github.com/gotd/td/issues/1711",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/gotd/td/issues/1711"
        },
        {
          "name": "https://github.com/gotd/td/commit/9d5d1f31ea5022d9798d84ccce15de2e91ba6baa",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/gotd/td/commit/9d5d1f31ea5022d9798d84ccce15de2e91ba6baa"
        },
        {
          "name": "https://github.com/gotd/td/releases/tag/v0.145.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/gotd/td/releases/tag/v0.145.1"
        }
      ],
      "source": {
        "advisory": "GHSA-whmm-qj9r-wvr2",
        "discovery": "UNKNOWN"
      },
      "title": "td has pre-auth denial of service via unbounded memory allocation in proto.UnencryptedMessage.Decode"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54638",
    "datePublished": "2026-07-28T22:14:53.550Z",
    "dateReserved": "2026-06-15T20:07:02.186Z",
    "dateUpdated": "2026-07-28T22:14:53.550Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-54638\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-28T23:17:08.617\",\"lastModified\":\"2026-07-28T23:17:08.617\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"gotd/td is a T Telegram MTProto API client in Go. Prior to 0.145.1, proto.UnencryptedMessage.Decode in proto/unencrypted_message.go read attacker controlled dataLen from an unauthenticated MTProto unencrypted packet and allocated make([]byte, dataLen) before checking the remaining buffer, allowing remote unauthenticated denial of service through excessive memory allocation and CPU or garbage collection pressure. This issue is fixed in version 0.145.1.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"gotd\",\"product\":\"td\",\"versions\":[{\"version\":\"\u003c 0.145.1\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-770\"},{\"lang\":\"en\",\"value\":\"CWE-789\"}]}],\"references\":[{\"url\":\"https://github.com/gotd/td/commit/9d5d1f31ea5022d9798d84ccce15de2e91ba6baa\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/gotd/td/issues/1711\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/gotd/td/releases/tag/v0.145.1\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/gotd/td/security/advisories/GHSA-whmm-qj9r-wvr2\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}

GHSA-WHMM-QJ9R-WVR2

Vulnerability from github – Published: 2026-07-28 22:15 – Updated: 2026-07-28 22:15

Summary

td has pre-auth denial of service via unbounded memory allocation in proto.UnencryptedMessage.Decode

Details

Impact

A remote, unauthenticated attacker can cause excessive memory allocation (and resulting CPU / GC pressure, potentially OOM termination) by sending a crafted unencrypted MTProto packet.

(*proto.UnencryptedMessage).Decode read an attacker-controlled 32-bit dataLen field and immediately allocated a buffer of that size via make([]byte, dataLen) before validating that the underlying buffer actually contained that many bytes. A 20-byte packet declaring a ~1.75 GB payload (e.g. dataLen = 0x70000000) forces the runtime to provision and zero-initialize a multi-gigabyte heap allocation before the length is rejected.

Unencrypted messages are part of the unauthenticated MTProto handshake path, so no credentials or established session are required to reach the vulnerable code.

Impact is limited to availability; there is no evidence of memory corruption, out-of-bounds access, or code execution.

Patches

Fixed in v0.145.1 by validating dataLen against the remaining buffer length before allocation (commit 9d5d1f31e).

Workarounds

Upgrade to v0.145.1 or later. There is no in-process workaround for affected versions short of avoiding exposure of the unauthenticated MTProto parsing path to untrusted peers.

Severity

7.5 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/gotd/td"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.145.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54638"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770",
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-28T22:15:28Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Impact\n\nA remote, unauthenticated attacker can cause excessive memory allocation (and resulting CPU / GC pressure, potentially OOM termination) by sending a crafted unencrypted MTProto packet.\n\n`(*proto.UnencryptedMessage).Decode` read an attacker-controlled 32-bit `dataLen` field and immediately allocated a buffer of that size via `make([]byte, dataLen)` **before** validating that the underlying buffer actually contained that many bytes. A 20-byte packet declaring a ~1.75 GB payload (e.g. `dataLen = 0x70000000`) forces the runtime to provision and zero-initialize a multi-gigabyte heap allocation before the length is rejected.\n\nUnencrypted messages are part of the unauthenticated MTProto handshake path, so no credentials or established session are required to reach the vulnerable code.\n\nImpact is limited to availability; there is no evidence of memory corruption, out-of-bounds access, or code execution.\n\n### Patches\n\nFixed in **v0.145.1** by validating `dataLen` against the remaining buffer length before allocation (commit `9d5d1f31e`).\n\n### Workarounds\n\nUpgrade to v0.145.1 or later. There is no in-process workaround for affected versions short of avoiding exposure of the unauthenticated MTProto parsing path to untrusted peers.",
  "id": "GHSA-whmm-qj9r-wvr2",
  "modified": "2026-07-28T22:15:28Z",
  "published": "2026-07-28T22:15:28Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/gotd/td/security/advisories/GHSA-whmm-qj9r-wvr2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gotd/td/issues/1711"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gotd/td/commit/9d5d1f31ea5022d9798d84ccce15de2e91ba6baa"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/gotd/td"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gotd/td/releases/tag/v0.145.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "td has pre-auth denial of service via unbounded memory allocation in proto.UnencryptedMessage.Decode"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
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.

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