---
id: "CVE-2026-62374"
kind: "vulnerability"
aliases: ["CVE-2026-62374"]
title: "SD-JWT JS: tampered disclosures silently dropped, claims reduced without error"
severity: "high"
cvss: 7.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["identity", "javascript", "node", "package", "sd-jwt"]
not_affected_if: ["key-binding-enforced", "no-sd-jwt-verification"]
published_at: "2026-10-29T17:18:10+00:00"
first_seen_at: "2026-10-29T17:26:17+00:00"
updated_at: "2026-10-29T17:27:57+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-62374", "first_seen_at": "2026-10-29T17:26:17+00:00"}]
---

# SD-JWT JS: tampered disclosures silently dropped, claims reduced without error

In SD JWT JS version 0.19.0 and earlier, the decoder silently discards a Disclosure whose digest does not match the signed claims and still reports the token as valid. A malicious holder, or an on-path attacker where key binding is not enforced, can remove claims and change an authorization decision without an error.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version of `@sd-jwt/core` and `@sd-jwt/decode` in your lockfile, for example `npm ls @sd-jwt/core @sd-jwt/decode`.
- Look for code that relies on `SDJwtInstance.verify()` results to grant access when an age, role or restriction claim is missing.
- Check whether key binding is required on your verification path.

## Fix

- `@sd-jwt/core` to `0.20.0`
- `@sd-jwt/decode`: no patched version identified

## Timeline

- 2026-10-29T17:26:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-62374

## From the sources

SD JWT JS is a JavaScript implementation of the Selective Disclosure JWT (SD-JWT) specification. In version 0.19.0 and earlier, `@sd-jwt/decode`, also used by `@sd-jwt/core`, silently drops a tampered Disclosure whose digest no longer matches the Issuer-signed `_sd` array and returns a reduced claim set, reporting success while the Issuer signature remains valid. Both a tampered Disclosure that remains valid JSON and a Disclosure containing invalid UTF-8 bytes reach this silent-drop behavior. In the latter case, the `TextDecoder / Buffer` decoding path substitutes U+FFFD replacement characters, recovering syntactically valid disclosure data instead of rejecting the malformed input. This violates RFC 9901 section 7.1 step 5, which requires rejection of unreferenced Disclosures, and section 7.1 step 3 / section 4.2.1, which require rejection of invalid Disclosures. A malicious holder can exploit this omission primitive, including through `SDJwtInstance.verify()` when key binding is required. An on-path attacker can also tamper with a Disclosure when the relying party does not enforce key binding; enforced key binding rejects on-path tampering because it invalidates the KB-JWT `sd_hash` binding. If the relying party defaults to allowing access when a constraining age, role, or restriction claim is absent, the silent claim reduction can change an authorization decision without an error. This issue is fixed in `@sd-jwt/core` version 0.20.0; no patched version of the standalone `@sd-jwt/decode` package is identified.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_