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.
\nAsh.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.
" }, { "base64": false, "type": "text/markdown", "value": "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.\n\n`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.\n\nThis issue affects ash: from 0.10.0 before 3.32.2." } ], "value": "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.\n\nAsh.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.\n\nThis issue affects ash: from 0.10.0 before 3.32.2." } ], "impacts": [ { "capecId": "CAPEC-492", "descriptions": [ { "lang": "en", "value": "CAPEC-492 Regular Expression Exponential Blowup" } ] } ], "metrics": [ { "cvssV4_0": { "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "baseScore": 5.9, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-400", "description": "CWE-400 Uncontrolled Resource Consumption", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-09-01T03:19:36.579Z" }, "references": [ { "tags": [ "vendor-advisory", "related" ], "url": "https://github.com/ash-project/ash/security/advisories/GHSA-mq7g-pffw-m8xh" }, { "tags": [ "related" ], "url": "https://cna.erlef.org/cves/CVE-2026-82735.html" }, { "tags": [ "related" ], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82735" }, { "tags": [ "patch" ], "url": "https://github.com/ash-project/ash/commit/14928412a1a94a69c47df8e98920d3a2b09cdec4" } ], "source": { "discovery": "EXTERNAL" }, "title": "Match regex runs on over-length input in Ash.Type.String, enabling regex denial of service" } } }