CVE-2026-55737
Full vulnerability record from the local CVENow database.
Description
Signed to Unsigned Conversion Error and Out-of-bounds Write vulnerability in Erlang OTP erts allows an attacker who can supply a crafted Erlang external term format (ETF) binary to binary_to_term/1 to corrupt the BEAM heap pointer and crash the virtual machine. When decoding a LARGE_TUPLE_EXT term, the validation pass decoded_size() in erts/emulator/beam/external.c reads the 32-bit arity field as unsigned (get_uint32()), while the decode pass dec_term() reads the same field as a signed 32-bit integer (get_int32()) into an int. An arity wire value of 0x80000000 passes validation as 2147483648 but decodes as -2147483648, so the subsequent hp += n moves the heap allocation pointer backward. Neither pass enforces the runtime tuple-arity limit MAX_ARITYVAL. The result is an out-of-bounds heap write; in practice the VM detects an impossible heap size and aborts, denying service. The required padding is large when uncompressed but the compressed-ETF envelope shrinks it to a small payload on the wire. This issue affects OTP from OTP 25.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to erts from 13.0 before 17.0.4, 16.4.0.4 and 15.2.7.11.
Severity
MEDIUM
CVSS score
5.1
(v4.0)
Vulnerability status
Analyzed
Source identifier
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Published
2026-07-27 16:17:48.847000
Last modified
2026-10-24 13:10:00.147000
View original CVE JSON
{
"id": "CVE-2026-55737",
"sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"published": "2026-07-27T16:17:48.847",
"lastModified": "2026-10-24T13:10:00.147",
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"value": "Signed to Unsigned Conversion Error and Out-of-bounds Write vulnerability in Erlang OTP erts allows an attacker who can supply a crafted Erlang external term format (ETF) binary to binary_to_term/1 to corrupt the BEAM heap pointer and crash the virtual machine.\n\nWhen decoding a LARGE_TUPLE_EXT term, the validation pass decoded_size() in erts/emulator/beam/external.c reads the 32-bit arity field as unsigned (get_uint32()), while the decode pass dec_term() reads the same field as a signed 32-bit integer (get_int32()) into an int. An arity wire value of 0x80000000 passes validation as 2147483648 but decodes as -2147483648, so the subsequent hp += n moves the heap allocation pointer backward. Neither pass enforces the runtime tuple-arity limit MAX_ARITYVAL. The result is an out-of-bounds heap write; in practice the VM detects an impossible heap size and aborts, denying service. The required padding is large when uncompressed but the compressed-ETF envelope shrinks it to a small payload on the wire.\n\nThis issue affects OTP from OTP 25.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to erts from 13.0 before 17.0.4, 16.4.0.4 and 15.2.7.11."
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"value": "La vulnerabilidad de error de conversión de firmado a no firmado y escritura fuera de límites en Erlang OTP erts permite a un atacante que puede proporcionar un binario de formato de término externo (ETF) de Erlang manipulado a binary_to_term/1 corromper el puntero del montón de BEAM y bloquear la máquina virtual.\n\nAl decodificar un término LARGE_TUPLE_EXT, el paso de validación decoded_size() en erts/emulator/beam/external.c lee el campo de aridad de 32 bits como no firmado (get_uint32()), mientras que el paso de decodificación dec_term() lee el mismo campo como un entero firmado de 32 bits (get_int32()) en un int. Un valor de aridad en la red de 0x80000000 pasa la validación como 2147483648 pero decodifica como -2147483648, por lo que el hp += n subsiguiente mueve el puntero de asignación del montón hacia atrás. Ninguno de los pasos aplica el límite de aridad de tupla en tiempo de ejecución MAX_ARITYVAL. El resultado es una escritura fuera de límites en el montón; en la práctica, la MV detecta un tamaño de montón imposible y aborta, denegando el servicio. El relleno requerido es grande cuando no está comprimido, pero la envoltura ETF comprimida lo reduce a una pequeña carga útil en la red.\n\nEste problema afecta a OTP desde OTP 25.0 antes de OTP 29.0.4, OTP 28.5.0.4 y OTP 27.3.4.15, correspondiente a erts desde 13.0 antes de 17.0.4, 16.4.0.4 y 15.2.7.11."
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