CVE-2026-77950: RPC error handler fails open in AshTypescript, disclosing unredacted errors

Severity: medium (CVSS 6.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-01 · updated 2026-09-01
Weakness: CWE-209

Description

Generation of Error Message Containing Sensitive Information vulnerability in ash-project ash_typescript allows an unauthenticated attacker to receive unredacted internal error data by provoking an error shape the configured error handler does not match. apply_error_handler/3 in lib/ash_typescript/rpc/errors.ex is the only hook an application has for redacting or suppressing errors before they reach the client, with a nil return dropping the error entirely. Its rescue clause logs a warning and then returns the original, pre-handler error map. Error handlers are conventionally written as pattern-matching functions over expected error shapes, so an unmatched shape raises FunctionClauseError and the raw transformed error, including any secrets carried in vars, is emitted instead. An intent to suppress an error becomes an intent to publish it. The rescue catches exceptions only, so a handler that throws or exits still propagates. This issue affects ash_typescript: from 0.8.0 before 0.18.0.

Affected products

ash-project ash_typescript: from 0.8.0 before 0.18.0 — fixed in 0.18.0

How to fix

Upgrade to a fixed version: ash-project ash_typescript 0.18.0. Check the vendor advisory for mitigations.

References

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