CVE-2026-55737
Signed to Unsigned Conversion Error and Out-of-bounds Write vulnerability in Erlang OTP erts allows an attacker who can supply a crafted Erl
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Published: Jul 27, 2026 · Last modified: Jul 27, 2026 · CWE-195 · CWE-787
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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.
- cna.erlef.orghttps://cna.erlef.org/cves/CVE-2026-55737.html
- github.comhttps://github.com/erlang/otp/commit/c5210b42a9d3d96f3d25601942ce8122be0f3761
- github.comhttps://github.com/erlang/otp/security/advisories/GHSA-446w-268v-9462
- osv.devhttps://osv.dev/vulnerability/EEF-CVE-2026-55737
- www.erlang.orghttps://www.erlang.org/doc/system/versions.html#order-of-versions