What is CVE-2026-32686?

CVE-2026-32686 is a medium-severity uncontrolled resource consumption vulnerability in decimal (erlang), affecting versions >= 0.1.0, < 3.0.0. It is fixed in 3.0.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.

Which versions of decimal are affected by CVE-2026-32686?

decimal (erlang) versions >= 0.1.0, < 3.0.0 is affected.

Is there a fix for CVE-2026-32686?

Yes. CVE-2026-32686 is fixed in 3.0.0. Upgrade to this version or later.

Is CVE-2026-32686 exploitable, and should I be worried?

Whether CVE-2026-32686 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-32686 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-32686 in decimal

Q: Which versions of decimal are affected by CVE-2026-32686?

decimal (erlang) versions >= 0.1.0, < 3.0.0 is affected.

Q: Is there a fix for CVE-2026-32686?

Yes. CVE-2026-32686 is fixed in 3.0.0. Upgrade to this version or later.

Q: Is CVE-2026-32686 exploitable, and should I be worried?

Whether CVE-2026-32686 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-32686 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-32686?

Upgrade decimal to 3.0.0 or later.

Summary

Decimal: Unbounded exponent in Decimal.new enables unauthenticated DoS

Summary
decimal doesn't bound the exponent on parsed input, so something like "1e10000000" is parsed fine but then explodes the memory to more than 7GB if you run e.g. Decimal.add(Decimal.parse("1e10000000"), 1) because for positive exp, the function tail-recurses with coef * 10 and exp - 1 per iteration, growing the bignum coefficient by one digit each step. In the worst case, one request is enough to OOM the BEAM.

Details

Decimal.new/parse/cast happily store huge exponents. After that, a bunch of core paths allocate proportional to exp:

add/sub/div go through add_align, which calls pow10(exp1 - exp2) and builds a giant bignum (lib/decimal.ex:1734-1738, 1827).
to_string/2 with :normal (also :xsd and the String.Chars impl) does :lists.duplicate(exp, ?0) (lib/decimal.ex:1506, 1513).
to_integer/1 recurses coef * 10, exp - 1 once per unit of exp (lib/decimal.ex:1603-1605).
round/3 does the same :lists.duplicate trick on the exp difference (lib/decimal.ex:1850, 1874).
compare/3 with a threshold argument loops back into add/sub, so it's vulnerable too (lib/decimal.ex:331-332).

PoC

Any of these will hang or OOM the BEAM:

Decimal.add(Decimal.new("1"), Decimal.new("1e1000000000"))
Decimal.to_string(Decimal.new("1e1000000000"), :normal)
Decimal.to_integer(Decimal.new("1e1000000000"))
Decimal.round(Decimal.new("1e1000000000"))

Impact

Unauthenticated remote DoS. Anything that takes a user-supplied decimal (JSON, form field, Ecto :decimal field, basically everywhere) and then does arithmetic, rounding, to_integer, or to_string on it is exposed. One request can kill the node with a Out-of-Memory exception.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

Affected versions

decimal (>= 0.1.0, < 3.0.0)

Security releases

decimal → 3.0.0 (erlang)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade decimal to 3.0.0 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-32686? CVE-2026-32686 is a medium-severity uncontrolled resource consumption vulnerability in decimal (erlang), affecting versions >= 0.1.0, < 3.0.0. It is fixed in 3.0.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
Which versions of decimal are affected by CVE-2026-32686? decimal (erlang) versions >= 0.1.0, < 3.0.0 is affected.
Is there a fix for CVE-2026-32686? Yes. CVE-2026-32686 is fixed in 3.0.0. Upgrade to this version or later.
Is CVE-2026-32686 exploitable, and should I be worried? Whether CVE-2026-32686 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-32686 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-32686? Upgrade decimal to 3.0.0 or later.