CVE-2026-82744: Ash.Reactor change step fails open, skipping a change when its where guard raises

Severity: low (CVSS 2.1 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-01 · updated 2026-09-01
Weakness: CWE-636

Description

Not Failing Securely (Failing Open) vulnerability in ash-project ash skips an Ash.Reactor change when the guard controlling it raises, so a change meant to run does not. An Ash.Reactor change step can be gated by where validations that decide whether the change runs. Ash.Reactor.ChangeStep (lib/ash/reactor/steps/change_step.ex) evaluated those guards in apply_where_clauses/3, and apply_validation rescued any exception into {:error, error}. The reduce treated that identically to a guard whose condition was simply not met and bypassed the change. So when a guard raises (for example on attacker-influenced input), a change that enforces a security-relevant modification is skipped rather than failing the step. The fix distinguishes a raised exception (now {:raised, error}) and halts the step with an error, failing closed. This issue affects ash: from 3.0.0-rc.17 before 3.32.2.

Affected products

ash-project ash: from 3.0.0-rc.17 before 3.32.2 — fixed in 3.32.2

How to fix

Upgrade to a fixed version: ash-project ash 3.32.2. Check the vendor advisory for mitigations.

References

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