CVE-2026-82741: CWE-1287 Improper Validation of Specified Type of Input in ash-project ash
Description
Improper Validation of Specified Type of Input vulnerability in ash-project ash lets an attacker confuse the stored type tag of an Ash.Type.Union value that uses storage: :map_with_tag, bypassing that member's validation and any tag-based authorization. For a union with storage: :map_with_tag, each member is identified in storage by a configured tag and tag_value. Ash.Type.Union.dump_to_native/2 (lib/ash/type/union.ex) did not force the configured tag when writing the value, so a tag carried in the submitted value was persisted verbatim. An attacker can therefore store a value whose data belongs to one member but whose tag names a different member. On read the value is re-selected by its tag and treated as the incompatible member (a type confusion), bypassing the real member's constraints and any logic or policy that branches on the union tag. The fix drops any incoming tag and forces the configured tag value on dump. This issue affects ash: from 2.14.18 before 3.32.2.
CVSS v4.0
Score 2.1low
Affected software
ash-project
ash
ash-project
ash
cpe:2.3:a:ash-project:ash:*:*:*:*:*:*:*:*Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in ash-project ash involves improper validation of the type tag in Ash.Type.Union values configured with storage :map_with_tag. The function responsible for serializing these union values did not enforce the configured tag, instead persisting the tag provided in the input verbatim. This allows an attacker to store a value with data belonging to one union member but tagged as a different member, causing type confusion on read. This bypasses the member's validation and any authorization logic based on the tag. The fix involves dropping any incoming tag and forcing the configured tag during serialization. The flaw affects ash versions from 2.14.18 before 3.32.2.
Potential Impact
An attacker can exploit this vulnerability to bypass validation and tag-based authorization by causing type confusion in union values. This could lead to unauthorized access or logic bypass in applications using the affected ash versions. The CVSS score of 2.1 indicates a low severity impact with local attack vector and low impact on confidentiality and integrity.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The described fix involves forcing the configured tag on serialization to prevent tag confusion. Until an official fix is confirmed, users should monitor vendor communications for patches addressing this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- EEF
- Date Reserved
- 2026-08-31T00:59:10.002Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a964c16acd9273b492d135b
Added to database: 09/01/2026, 03:52:54 UTC
Last enriched: 09/07/2026, 14:46:34 UTC
Last updated: 10/15/2026, 18:48:24 UTC
Views: 81
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