CVE-2026-32686 Unbounded exponent in decimal enables unauthenticated DoS
Attackers can crash the BEAM VM by sending decimal inputs with huge exponents, causing memory exhaustion in applications using the decimal library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32686?
CVE-2026-32686 is a medium-severity denial of service vulnerability in ericmj decimal, published on 7 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-400
Which versions are affected by CVE-2026-32686?
3 open source packages ship an affected version, including decimal.
| Package | Affected | Fixed in |
|---|---|---|
decimal Hex | From 0.1.0 | 3.0.0 |
decimal Hex | From 0.1.0 | 3.0.0 |
decimal Hex | From 0.1.0 | 3.0.0 |
How do I fix CVE-2026-32686?
Upgrade decimal to 3.0.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-32686 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32686 exists.
Sources
Also known as EEF-CVE-2026-32686, GHSA-rhv4-8758-jx7v.