Weakness Type (CWE)

CWE-191 — CWE-191 Integer Underflow (Wrap or Wraparound)

CAPEC

CVSS 4.0 Score

8.2

HIGH

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability description

Integer Underflow (Wrap or Wraparound) vulnerability in erlang otp erlang/otp (erts modules), erlang otp erts (erts modules) allows Forced Integer Overflow, Excessive Allocation. This vulnerability is associated with program files erts/emulator/beam/external.c, emulator/beam/external.c.

The BIT_BINARY_EXT tag (77) handler in the External Term Format (ETF) decoder accepts an encoding with both length and trailing-bits fields set to zero. The subsequent computation of the bitstring size underflows an unsigned integer, producing a value of roughly 2^64 that is then passed as a memory allocation size. The allocator aborts the entire node with a message such as Cannot allocate 2305843009213693951 bytes of memory (of type "binary").

The crash is a VM-level abort, not an Erlang-level exception. It cannot be intercepted by supervision trees, by try/catch, or by passing the [safe] option to binary_to_term/2 (which only restricts atom creation and does not perform structural validation of binary encodings).

Any application that decodes ETF from untrusted sources via binary_to_term/1,2 or enif_binary_to_term() is exposed. The Erlang distribution protocol also decodes incoming terms through the same code path, but distribution is expected to run on trusted networks per the OTP Secure Coding Guidelines (DSG-011).

This issue affects OTP from OTP 27.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to erts from 15.0 before 17.0.4, 16.4.0.4 and 15.2.7.11.

Affected

pkg:otp/erts

Module Source File Routine
erts emulator/beam/external.c erlang:binary_to_term/1
erlang:binary_to_term/2
Status Type Version Changes / Fixed in
affected otp ⓘ 15.0
  • unaffected at 15.2.7.11
  • unaffected at 16.4.0.4
  • unaffected at 17.0.4

pkg:github/erlang/otp

Module Source File Routine
erts erts/emulator/beam/external.c erlang:binary_to_term/1
erlang:binary_to_term/2
Status Type Version Changes / Fixed in
affected otp ⓘ 27.0
affected git ⓘ 24ef4cbaed < dc1bf9344c

Workarounds

Do not call binary_to_term/1,2 or enif_binary_to_term() on data from untrusted sources. The OTP Secure Coding Guidelines (DSG-011) recommend avoiding these functions altogether on untrusted input and using an alternative serialization format (for example JSON or Protocol Buffers) instead.

References

Credits

  • Finder: Paul Guyot
  • Finder: Lukas Backström
  • Remediation developer: John Högberg

CVE record as JSON:  GET /cves/CVE-2026-54890.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-54890.json