CVE-2026-31976
xygeni-action is the GitHub Action for Xygeni Scanner. On March 3, 2026, an attacker with access to compromised credentials created a series of pull requests (#46, #47, #48) injecting obfuscated shell code into action.yml. The PRs were blocked by branch protection rules and never merged into the main branch. However, the attacker used the compromised GitHub App credentials to move the mutable v5 tag to point at the malicious commit (4bf1d4e19ad81a3e8d4063755ae0f482dd3baf12) from one of the unmerged PRs.
Leer descripción completaMostrar menos
This commit remained in the repository's git object store, and any workflow referencing @v5 would fetch and execute it. This is a supply chain compromise via tag poisoning. Any GitHub Actions workflow referencing xygeni/xygeni-action@v5 during the affected window (approximately March 3–10, 2026) executed a C2 implant that granted the attacker arbitrary command execution on the CI runner for up to 180 seconds per workflow run.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 9.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.83%
- Percentil entre todas las CVEs puntuadas: 56
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1195Supply Chain Compromiseinitial access95 % - Impacto principal
T1059Command and Scripting Interpreterexecution90 % - Impacto secundario
T1005Data from Local Systemcollection75 % - Impacto secundario
T1537Transfer Data to Cloud Accountexfiltration70 %
Compromiso de cadena de suministro mediante envenenamiento de etiqueta en repositorio público (tag v5 manipulado). Ejecución de código arbitrario (shell C2) en CI runners y acceso a datos de construcción.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
CWE
- CWE-506
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-31976",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-31976",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-03-12T19:54:48.032219Z"
}
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 9.8,
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 3.9
}
],
"cvssMetricV40": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 9.3,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"exploitMaturity": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"privilegesRequired": "NONE",
"subIntegrityImpact": "NONE",
"vulnIntegrityImpact": "HIGH",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "HIGH",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "NONE",
"vulnConfidentialityImpact": "HIGH",
"confidentialityRequirement": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
}
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "xygeni",
"product": "xygeni-action",
"versions": [
{
"status": "affected",
"version": ">= March 3, 2026, <= March 10, 2026"
}
]
}
]
}
],
"published": "2026-03-11T20:16:17.440",
"references": [
{
"url": "https://github.com/xygeni/xygeni-action/issues/54",
"tags": [
"Issue Tracking"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/xygeni/xygeni-action/security/advisories/GHSA-f8q5-h5qh-33mh",
"tags": [
"Patch",
"Vendor Advisory"
],
"source": "security-advisories@github.com"
}
],
"vulnStatus": "Analyzed",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-506"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "xygeni-action is the GitHub Action for Xygeni Scanner. On March 3, 2026, an attacker with access to compromised credentials created a series of pull requests (#46, #47, #48) injecting obfuscated shell code into action.yml. The PRs were blocked by branch protection rules and never merged into the main branch. However, the attacker used the compromised GitHub App credentials to move the mutable v5 tag to point at the malicious commit (4bf1d4e19ad81a3e8d4063755ae0f482dd3baf12) from one of the unmerged PRs. This commit remained in the repository's git object store, and any workflow referencing @v5 would fetch and execute it. This is a supply chain compromise via tag poisoning. Any GitHub Actions workflow referencing xygeni/xygeni-action@v5 during the affected window (approximately March 3–10, 2026) executed a C2 implant that granted the attacker arbitrary command execution on the CI runner for up to 180 seconds per workflow run."
},
{
"lang": "es",
"value": "xygeni-action es la Acción de GitHub para Xygeni Scanner. El 3 de marzo de 2026, un atacante con acceso a credenciales comprometidas creó una serie de solicitudes de extracción (#46, #47, #48) inyectando código shell ofuscado en action.yml. Las solicitudes de extracción fueron bloqueadas por las reglas de protección de rama y nunca se fusionaron en la rama principal. Sin embargo, el atacante utilizó las credenciales comprometidas de la aplicación de GitHub para mover la etiqueta mutable v5 para que apuntara al commit malicioso (4bf1d4e19ad81a3e8d4063755ae0f482dd3baf12) de una de las solicitudes de extracción no fusionadas. Este commit permaneció en el almacén de objetos git del repositorio, y cualquier flujo de trabajo que hiciera referencia a @v5 lo recuperaría y ejecutaría. Esto es un compromiso de la cadena de suministro mediante envenenamiento de etiquetas. Cualquier flujo de trabajo de GitHub Actions que hiciera referencia a xygeni/xygeni-action@v5 durante la ventana afectada (aproximadamente del 3 al 10 de marzo de 2026) ejecutó un implante C2 que otorgó al atacante ejecución arbitraria de comandos en el ejecutor de CI por hasta 180 segundos por ejecución de flujo de trabajo."
}
],
"lastModified": "2026-06-17T10:34:52.610",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:xygeni:xygeni-action:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "432E19E2-DDB5-4EBB-A540-A07106448E76",
"versionEndIncluding": "6.4.0",
"versionStartIncluding": "5.38.0"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security-advisories@github.com"
}