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Fencer Vulns
high 7.5

CVE-2026-54890 json

BEAM VM crash via integer underflow in binary_to_term BIT_BINARY_EXT decoding

published 2026-07-27 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-49326

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

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.

Patch / fix

  • Erlang OTP 15.2.7.11, 16.4.0.4, 17.0.4, 27.3.4.15, 28.5.0.4, 29.0.4
  • erlang Debian 13 1:27.3.4.1+dfsg-1+deb13u3
  • erlang Debian 14 1:29.0.4+dfsg-1

debian advisories DEBIAN-CVE-2026-54890

  • erlang Ubuntu 26.04 LTS 1:27.3.4.6+dfsg-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2026-54890

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • erlang27 hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-et hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-wx hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-ftp hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-ssh hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-ssl hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-asn1 hummingbird 1 27.3.4.15-0.1.hum1
  • erlang27-edoc hummingbird 1 27.3.4.15-0.1.hum1

red hat advisories RHSA-2026:47009

  • erlang openSUSE Tumbleweed 28.5.0.4-1.1
  • erlang27 openSUSE Tumbleweed 27.1.3-3.1

opensuse advisories openSUSE-SU-2026:11559-1openSUSE-SU-2026:11560-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-54890 updated cvss 7.5

erlang/otp: erts: otp: Erlang/OTP: Denial of Service via integer underflow in ETF decoding

  • Red Hat Hardened Images erlang27 27.3.4.15-0.1.hum1
    fixed: vendor fix RHSA-2026:47009

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 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
CNA 4.0 8.2 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Erlang OTP

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)
  • CWE-789 Memory Allocation with Excessive Size Value
  • CWE-1284 Improper Validation of Specified Quantity in Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.