MAL-2026-13745

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/base65-11x/MAL-2026-13745.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-13745
Aliases
  • GHSA-39c6-h85q-hpcw
Published
2026-08-11T16:40:06Z
Modified
2026-08-12T00:30:12Z
Summary
Malicious code in base65-11x (npm)
Details

-= Per source details. Do not edit below this line.=-

Source: amazon-inspector (14cc9506a804a2663d0cde1c610fa8cba5733e6797652b6365569ada5ef3901d)

base65-11x is a name-lookalike of the widely used base-x encoder. Both entrypoints (src/cjs/index.cjs and src/esm/index.js, ~127KB each vs. ~4KB for real base-x) contain the legitimate base-x source followed by a ~123KB single-line obfuscated payload wrapped in a custom-VM IIFE (identifiers vmN, vmA_ab9191, vmU_d6a896; Object.defineProperty-based dispatch on a global slot). The payload sits at module top level, so it executes automatically whenever a consumer require()s or import()s the package. A pure base-encoding utility has no functional need for runtime-VM-packed code on load, and the payload is duplicated across CJS and ESM entrypoints to ensure execution regardless of module system. The specific payload behavior is concealed inside the VM interpreter and cannot be recovered without executing it.

Source: ghsa-malware (672a03fa0011f4095fdff19eaa7e65ffa8ae44f34e673a707488903c5b6eab67)

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Database specific
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-017379",
            "import_time": "2026-08-11T18:52:00.276273648Z",
            "modified_time": "2026-08-11T18:48:52Z",
            "sha256": "14cc9506a804a2663d0cde1c610fa8cba5733e6797652b6365569ada5ef3901d",
            "source": "amazon-inspector",
            "versions": [
                "5.0.2"
            ]
        },
        {
            "id": "GHSA-39c6-h85q-hpcw",
            "import_time": "2026-08-12T00:17:04.853118565Z",
            "modified_time": "2026-08-11T16:40:07Z",
            "ranges": [
                {
                    "events": [
                        {
                            "introduced": "0"
                        }
                    ],
                    "type": "SEMVER"
                }
            ],
            "sha256": "672a03fa0011f4095fdff19eaa7e65ffa8ae44f34e673a707488903c5b6eab67",
            "source": "ghsa-malware"
        }
    ]
}
References
Credits

Affected packages

npm / base65-11x

Package

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.0.2

Database specific

cwes
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    },
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]
indicators
{
    "evidence_files": [
        {
            "path": "src/cjs/index.cjs",
            "sha256": "fee94eeb5aff293894efe1b9614720d4898ad03181ff3c3344005a529f08c7eb",
            "tlsh": "89c3c84067e6747e507e62e08b5be201b903afb3420918fd8f64fb694db034959e7f1a"
        },
        {
            "path": "src/esm/index.js",
            "sha256": "6f2f987f5d25edb054f80cbd9554e91c723763781fb5f07be746a0222484eb11",
            "tlsh": "79c3c84067e6747e507e62e08b5be201b903afa3420918fd8f64fb694db034959e7f1a"
        }
    ]
}
source
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/base65-11x/MAL-2026-13745.json"