CVE-2026-49419
Full vulnerability record from the local CVENow database.
Description
When the JAIL_AT_DESC flag is specified, kern_jail_set() and kern_jail_get() released the reference to the caller's current prison before looking up the jail descriptor. If the descriptor lookup failed, error-handling paths released the same reference a second time. An unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use. When this is done on the jail host, the bug will generally result in an immediate panic. However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges.
Severity
HIGH
CVSS score
8.8
(v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-08-19 05:17:04.053000
Last modified
2026-11-05 20:10:00.200000
View original CVE JSON
{
"id": "CVE-2026-49419",
"sourceIdentifier": "[email protected]",
"published": "2026-08-19T05:17:04.053",
"lastModified": "2026-11-05T20:10:00.200",
"vulnStatus": "Analyzed",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "When the JAIL_AT_DESC flag is specified, kern_jail_set() and kern_jail_get() released the reference to the caller's current prison before looking up the jail descriptor. If the descriptor lookup failed, error-handling paths released the same reference a second time.\n\nAn unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use. When this is done on the jail host, the bug will generally result in an immediate panic. However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges."
},
{
"lang": "es",
"value": "Cuando se especifica la bandera JAIL_AT_DESC, kern_jail_set() y kern_jail_get() liberaron la referencia a la prisión actual del llamador antes de buscar el descriptor de jail. Si la búsqueda del descriptor fallaba, las rutas de manejo de errores liberaban la misma referencia una segunda vez.\n\nUn usuario local sin privilegios puede desencadenar un desbordamiento negativo del contador de referencias de prisión, lo que puede causar que la estructura de prisión sea liberada mientras aún está en uso. Cuando esto se hace en el host de jail, el error generalmente resultará en un pánico inmediato. Sin embargo, si el usuario se está ejecutando en un jail, entonces puede ser posible exploit el error para elevar privilegios."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "FreeBSD",
"product": "FreeBSD",
"defaultStatus": "unknown",
"modules": [
"jail"
],
"versions": [
{
"version": "15.1-RELEASE",
"lessThan": "p1",
"versionType": "release",
"status": "affected"
},
{
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"versionType": "release",
"status": "affected"
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}
]
}
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"baseScore": 8.8,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
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"id": "CVE-2026-49419",
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{
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{
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"role": "CISA Coordinator",
"version": "2.0.3"
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"source": "[email protected]",
"type": "Secondary",
"description": [
{
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"value": "CWE-911"
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"references": [
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"url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:38.jail.asc",
"source": "[email protected]",
"tags": [
"Vendor Advisory"
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}
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}