CVE-2026-73252

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Source

https://cve.org/CVERecord?id=CVE-2026-73252

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73252.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-73252

Aliases

GHSA-hq58-98f5-2wg3

Downstream

Published

2026-10-14T18:24:16Z

Modified

2026-10-28T11:23:03Z

Severity

7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator

Summary

Mongoose: Unauthenticated remote heap out-of-bounds read in built-in TLS: off-by-one length check in mg_tls_recv_record() underflows recv_len to SIZE_MAX

Details

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS stack selected by MG_TLS_BUILTIN in src/tls_builtin.c accepts a TLS 1.3 record whose decrypted size is exactly the 16-byte authentication tag with no plaintext or ContentType byte. In mg_tls_recv_record(), the msgsz length check permits that record and the recv_len calculation underflows to SIZE_MAX, so a later handshake step treats stale buffer contents as a trusted message with an effectively unbounded length. An unauthenticated malicious TLS peer can trigger a heap out-of-bounds read before certificate or Finished validation, causing a remote denial of service. This issue is fixed in version 7.23.

Database specific

{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-125",
        "CWE-191"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73252.json"
}

References

Affected packages

Git / github.com/cesanta/mongoose

Affected ranges

Type

GIT

Repo

https://github.com/cesanta/mongoose

Events

Introduced

Fixed

02bdbb9ed6f0a8f7c42228c6e7cb35d748b60551

Fixed

758e301f0c9a9885c1b716195df5fe6d6ac9d53e

Database specific

Show details

{
    "extracted_events": [
        {
            "range": [
                {
                    "introduced": "0"
                },
                {
                    "fixed": "7.23"
                }
            ],
            "source": "AFFECTED_FIELD",
            "strategy": "StringRangeExpression"
        },
        {
            "range": [
                {
                    "fixed": "758e301f0c9a9885c1b716195df5fe6d6ac9d53e"
                }
            ],
            "source": "REFERENCES_COMMIT"
        },
        {
            "original_tag": "7.23",
            "range": [
                {
                    "fixed": "02bdbb9ed6f0a8f7c42228c6e7cb35d748b60551"
                }
            ],
            "source": "REFERENCES_TAG"
        }
    ]
}

Affected versions

3.*

3.2

3.3

3.4

3.5

3.6

3.7

3.8

4.*

4.0

4.1

5.*

5.0

5.1

5.2

5.3

5.4

5.5

5.5_20140120

5.6

6.*

6.0

6.1

6.10

6.11

6.12

6.13

6.14

6.15

6.16

6.17

6.18

6.2

6.3

6.4

6.5

6.6

6.7

6.9

7.*

7.0

7.1

7.11

7.12

7.13

7.14

7.15

7.16

7.17

7.18

7.19

7.2

7.20

7.21

7.22

7.3

7.4

7.5

7.6

7.7

7.8

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73252.json"

vanir_signatures

[
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "86443508835696488587883280235325499731",
                "50764294704973727525865718954909852706",
                "230632011381914703751982248782942108460",
                "176719577680478611148017368742084149500"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-73252-2a4dea94",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/cesanta/mongoose/commit/758e301f0c9a9885c1b716195df5fe6d6ac9d53e",
        "target": {
            "file": "src/tls_builtin.c"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "function_hash": "205139962718063754017149212072420838454",
            "length": 2627
        },
        "id": "CVE-2026-73252-4c1d8e57",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/cesanta/mongoose/commit/758e301f0c9a9885c1b716195df5fe6d6ac9d53e",
        "target": {
            "file": "src/tls_builtin.c",
            "function": "mg_tls_recv_record"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "function_hash": "205139962718063754017149212072420838454",
            "length": 2627
        },
        "id": "CVE-2026-73252-6e9758e8",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/cesanta/mongoose/commit/758e301f0c9a9885c1b716195df5fe6d6ac9d53e",
        "target": {
            "file": "mongoose.c",
            "function": "mg_tls_recv_record"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "86443508835696488587883280235325499731",
                "50764294704973727525865718954909852706",
                "230632011381914703751982248782942108460",
                "176719577680478611148017368742084149500"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-73252-6ed0198f",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/cesanta/mongoose/commit/758e301f0c9a9885c1b716195df5fe6d6ac9d53e",
        "target": {
            "file": "mongoose.c"
        }
    }
]

vanir_signatures_modified

"2026-10-28T11:23:03Z"