CVE-2026-82735 Match regex runs on over-length input in Ash.Type.String, enabling regex denial of service
Attackers can cause CPU exhaustion by sending over-length input to Ash.Type.String, bypassing length checks before regex evaluation.
- 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-2026-82735?
CVE-2026-82735 is a medium-severity denial of service vulnerability in ash-project ash, published on 1 Sep 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 ash-project ash allows an attacker to force an expensive regular expression to run on input that a length constraint should have already rejected.
Ash.Type.String.apply_constraints/2 (lib/ash/type/string.ex) evaluated the :match regex regardless of the min_length and max_length constraints on the same attribute. Because the length check did not gate the regex, an over-length value that the length constraint rejects still had the pattern applied to it, so the length limit that would otherwise bound the work never constrained the regex input. Against a backtracking pattern this yields catastrophic regex evaluation on attacker-sized input, and even a linear pattern runs on arbitrarily large input, consuming CPU per request. The fix skips the :match regex whenever a length constraint is violated, making the two checks order-independent.
This issue affects ash: from 0.10.0 before 3.32.2.
Weakness: CWE-400
Which versions are affected by CVE-2026-82735?
1 open source package ship an affected version, including ash.
| Package | Affected | Fixed in |
|---|---|---|
ash Hex | From 0.10.0 | 3.32.2 |
How do I fix CVE-2026-82735?
Upgrade ash to 3.32.2 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-2026-82735 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82735 exists.
Sources
Also known as EEF-CVE-2026-82735, GHSA-mq7g-pffw-m8xh.