EEF-CVE-2026-82735 CVE-2026-82735 GHSA-mq7g-pffw-m8xh
Match regex runs on over-length input in Ash.Type.String, enabling regex denial of service
- Severity
- 0.0 / 10
- Unknown · CVSS 4.0
- Exploit chance (EPSS)
- 0.18%
- Chance of exploitation in the next 30 days. Higher than 7.56% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
3.32.2- Upgrade ash to this version or later
Description
Summary
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.
Affected versions
Hex
| Package | Vulnerable | Fixed in |
|---|---|---|
| ash | >= 0.10.0, < 3.32.2 |
3.32.2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
ash Hex → 3.32.2
- mix
{:ash, "~> 3.32.2"} # then: mix deps.update ash
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Attack vector
- Local
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-96581 An upsert on the primary key in Ash ignores attribute multitenancy, so one tenant can read, overwrite and take over another tenant's records | Not rated yet | Also affects ash |
| EEF-CVE-2026-114214 Loading a through relationship with a limit of 1 in Ash ignores the through path and returns unrelated destination records | Not rated yet | Also affects ash |
| EEF-CVE-2026-101028 Ash.count, Ash.exists and Ash.aggregate skip related resources' read policies in filters and sorts | Not rated yet | Also affects ash |
| EEF-CVE-2026-94201 Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash | Not rated yet | Also affects ash |
| EEF-CVE-2026-93477 Private action arguments can be set by user input on the bulk destroy and bulk update paths in Ash | Not rated yet | Also affects ash |
| EEF-CVE-2026-86338 Ash field policies do not filter-nil forbidden calculations and aggregates, enabling an information-disclosure oracle | Not rated yet | Also affects ash |
| EEF-CVE-2026-82752 Ash string length constraints count graphemes, so a combining-mark string of any size passes max_length | Not rated yet | Also affects ash |
| EEF-CVE-2026-82747 Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor | Not rated yet | Also affects ash |
Credits: Jonatan Männchen / EEF, Peter Ullrich, Zach Daniel / Ash Project
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