# CVE-2026-89319: Thales gose JweDirectDecryptorBlock unchecked length header

Source: https://junglewise.ai/threats/cve-2026-89319-jwedirectdecryptorblock-decrypt-read-a-64-bit-plaintext-length  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-23. Updated: 2026-10-23  
License: CC BY 4.0 with a link back

CVE-2026-89319 · Severity: info · Published 2026-10-23

Thales gose is a cryptography library used for JSON Web Encryption (JWE) operations. The AES-CBC-HMAC decryption function fails to validate a 64-bit length field in the protected header, allowing an attacker who has seen one valid JWE to craft a malicious message that causes a denial-of-service panic or memory exhaustion without knowing the encryption key.

Technologies: [Eclipse KeyPont Gose](https://junglewise.ai/threats/technologies/eclipse-keypont-gose), [Thales Gose](https://junglewise.ai/threats/technologies/gose). Vendors: [Eclipse KeyPont](https://junglewise.ai/threats/vendors/eclipse-keypont), [Thales](https://junglewise.ai/threats/vendors/thales).

## Quick answers

**Is CVE-2026-89319 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-89319 being exploited in the wild.

**How severe is CVE-2026-89319?** Informational severity, published 23 October 2026.

**Which products and versions are affected?** Eclipse KeyPont Gose before 1.0.0-rc1; Thales Gose 0.9.0 through 0.13.0-rc1.

**Is there a fix for CVE-2026-89319?** Yes: fixed in Thales gose 1.0.0-rc1 (eclipse-keypont/gose: any version 1.0.0-rc1 or later). Until then: Upgrade to the patched version. Prior to upgrading, applications should be aware that observed valid JWEs can be reused with forged _thales_aad headers to trigger denial of service. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-89319 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-89319?** Check whether you run Eclipse KeyPont Gose or Thales Gose at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Thales gose 1.0.0-rc1 (eclipse-keypont/gose: any version 1.0.0-rc1 or later)

Upgrade to the patched version. Prior to upgrading, applications should be aware that observed valid JWEs can be reused with forged _thales_aad headers to trigger denial of service.

## Technical details

JweDirectDecryptorBlock.Decrypt reads an unvalidated 64-bit plaintext length from the _thales_aad protected-header field after the HMAC integrity check. Three failure modes result: a nil header causes a nil pointer dereference, a truncated field panics in binary.BigEndian.Uint64, and an oversized length triggers unbounded allocation or slice-bounds panic. Although the HMAC check ordinarily gates this, a related vulnerability (GHSA-h6w5-722x-2h3m) breaks authentication in all affected releases, allowing reuse of any observed tag on forged content.

## Affected products

- Thales gose 0.9.0 through 0.13.0-rc1
- Eclipse Keypont gose before 1.0.0-rc1

## Timeline

- 2024-08-02: other: Vulnerability introduced in commit b7b140e, adding AES-CBC-then-HMAC support
- 2026-09-01: disclosed: GHSA-4gj8-hg2r-gw6q advisory published
- 2026-10-23: advisory: CVE-2026-89319 published on NVD
- 2026: patched: Fixed in commit 3d1b063 (released as v1.0.0-rc1)

## References

- [https://github.com/eclipse-keypont/gose/security/advisories/GHSA-4gj8-hg2r-gw6q](https://github.com/eclipse-keypont/gose/security/advisories/GHSA-4gj8-hg2r-gw6q)

## Related threats

- [gose JweRsaKeyEncryptionDecryptorImpl panic on invalid IV length](https://junglewise.ai/threats/cve-2026-89318-jwersakeyencryptiondecryptorimpl-decrypt-passed-the-jwe-s)
- [gose JWS critical header bypass in JWT verification](https://junglewise.ai/threats/cve-2026-89317-gose-parsed-the-jws-crit-header-into-jwsheader-crit-and-then)
- [gose JwtClaims.MarshalJSON panic in reflect.StructOf](https://junglewise.ai/threats/cve-2026-89315-jwtclaims-marshaljson-built-a-go-struct-at-runtime-with-reflect)
- [Eclipse KeyPont gose quadratic time key_ops validation DoS](https://junglewise.ai/threats/cve-2026-89314-jwkfields-checkconsistency-detected-duplicate-key-ops-entries)
- [eclipse-keypont gose JwksTrustStore.Get returns wrong key on absent kid](https://junglewise.ai/threats/cve-2026-89313-jwkstruststore-get-assigned-each-parsed-key-to-the-function-s)