CVE-2026-32686: Unbounded exponent in decimal enables unauthenticated DoS

Severity: medium (CVSS 6.9 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-07 · updated 2026-10-26
Weakness: CWE-400

Description

Uncontrolled Resource Consumption vulnerability in ericmj decimal allows unauthenticated remote Denial of Service. The decimal library does not bound the exponent on parsed input. Storing a decimal with a very large exponent (e.g. Decimal.new("1e1000000000")) is accepted without error. Subsequent calls to arithmetic functions (Decimal.add/2, Decimal.sub/2, Decimal.div/2M), Decimal.to_string/2M with :normalM or :xsdM format, Decimal.to_integer/1M, Decimal.round/3M, or Decimal.compare/3M with a threshold allocate memory proportional to the exponent value, which can exhaust available memory and crash the BEAM VM. Any application that accepts user-supplied decimal input and subsequently performs arithmetic, rounding, conversion to integer, or string formatting on it is exposed. A single malicious request is sufficient to cause an out-of-memory crash. This issue affects decimal: from 0.1.0 before 3.0.0.

Affected products

ericmj decimal: from 0.1.0 before 3.0.0 — fixed in 3.0.0

How to fix

Upgrade to a fixed version: ericmj decimal 3.0.0. Check the vendor advisory for mitigations.

References

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