{"id":"UBUNTU-CVE-2026-55737","details":"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.","modified":"2026-09-22T22:55:12.392941212Z","published":"2026-07-27T16:17:00Z","upstream":["CVE-2026-55737"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-55737"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-55737"}],"affected":[{"package":{"name":"erlang","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/erlang?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:25.2.3+dfsg-1","1:25.3.2.8+dfsg-1","1:25.3.2.8+dfsg-1ubuntu1","1:25.3.2.8+dfsg-1ubuntu3","1:25.3.2.8+dfsg-1ubuntu4","1:25.3.2.8+dfsg-1ubuntu4.1","1:25.3.2.8+dfsg-1ubuntu4.2","1:25.3.2.8+dfsg-1ubuntu4.3","1:25.3.2.8+dfsg-1ubuntu4.4","1:25.3.2.8+dfsg-1ubuntu4.5","1:25.3.2.8+dfsg-1ubuntu4.6"],"ecosystem_specific":{"binaries":[{"binary_name":"erlang","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-asn1"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-base"},{"binary_name":"erlang-common-test","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-crypto","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-debugger","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-dialyzer","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-diameter","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-edoc","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-eldap","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-erl-docgen","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-et"},{"binary_name":"erlang-eunit","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-examples"},{"binary_name":"erlang-ftp","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-inets","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-jinterface","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-manpages"},{"binary_name":"erlang-megaco","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-mnesia"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-mode"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-nox"},{"binary_name":"erlang-observer","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-odbc","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-os-mon","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-parsetools","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-public-key"},{"binary_name":"erlang-reltool","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-runtime-tools","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-snmp","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-src"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-ssh"},{"binary_name":"erlang-ssl","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-syntax-tools","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-tftp","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-tools"},{"binary_name":"erlang-wx","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_name":"erlang-x11","binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6"},{"binary_version":"1:25.3.2.8+dfsg-1ubuntu4.6","binary_name":"erlang-xmerl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55737.json"}},{"package":{"name":"erlang","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/erlang?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:27.3.4.1+dfsg-1build1","1:27.3.4.3+dfsg-1","1:27.3.4.4+dfsg-1","1:27.3.4.6+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_name":"erlang","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-asn1","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-base","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-common-test","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-crypto","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-debugger","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-dialyzer","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-diameter","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-edoc","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_name":"erlang-eldap","binary_version":"1:27.3.4.6+dfsg-1"},{"binary_versi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