CVE-2026-82735
Match regex runs on over-length input in Ash.Type.String, enabling regex denial of service
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.
INFO
Published Date :
Sept. 1, 2026, 4:18 a.m.
Last Modified :
Sept. 1, 2026, 4:18 a.m.
Remotely Exploit :
No
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update ash-project ash to version 3.32.2 or later.
- Ensure regex evaluations are gated by length constraints.
- Apply length constraints before regex pattern matching.
- Validate input lengths before processing.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-82735.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-82735
weaknesses.
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The following table lists the changes that have been made to the
CVE-2026-82735 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Sep. 01, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-400 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/82xxx/CVE-2026-82735.json">CVE-2026-82735</a> Added Reference https://cna.erlef.org/cves/CVE-2026-82735.html Added Reference https://github.com/ash-project/ash/commit/14928412a1a94a69c47df8e98920d3a2b09cdec4 Added Reference https://github.com/ash-project/ash/security/advisories/GHSA-mq7g-pffw-m8xh Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-82735