# CVE-2026-81703: openssl_encrypt authentication bypass in post-quantum key validation

Source: https://junglewise.ai/threats/cve-2026-81703-openssl-encrypt-authentication-bypass-in-post-quantum-key  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-27. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-81703 · Severity: medium · CVSS 5.5 · Published 2026-08-27

openssl_encrypt is a tool for encrypting and decrypting files using password-based encryption with support for post-quantum cryptography. Versions before 1.4.9 fail to validate whether embedded post-quantum private keys are properly encrypted, allowing attackers to craft malicious files that decrypt under any password and falsely claim to be integrity-verified. This bypasses the authentication mechanism entirely, potentially allowing attackers to distribute trojan files that users will unknowingly accept as legitimate.

Technologies: [Jahlives Openssl Encrypt](https://junglewise.ai/threats/technologies/openssl-encrypt), [openssl-encrypt (PyPI)](https://junglewise.ai/threats/technologies/pypi-openssl-encrypt). Vendors: [Jahlives](https://junglewise.ai/threats/vendors/jahlives), [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-81703 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-81703 being exploited in the wild.

**How severe is CVE-2026-81703?** Medium severity, with a CVSS score of 5.5, published 27 August 2026.

**Which products and versions are affected?** Jahlives Openssl Encrypt before 1.4.9; openssl-encrypt (PyPI) ECOSYSTEM:introduced=0,fixed=1.4.9.

**Is there a fix for CVE-2026-81703?** Yes. openssl-encrypt (PyPI): upgrade to 1.4.9 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-81703 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-81703?** Check whether you run Jahlives Openssl Encrypt or openssl-encrypt (PyPI) 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

- openssl-encrypt (PyPI): upgrade to 1.4.9 or later

  ```sh
  pip install "openssl-encrypt>=1.4.9"
  ```


## Technical details

The vulnerability is an improper authentication flaw (CWE-287) in the decrypt_file function. The vulnerable code trusts unencrypted embedded post-quantum private keys in file metadata when the pqc_key_encrypted field is absent or false; for mayo/cross/ML-KEM hybrid algorithms, decryption derives the bulk key only from this embedded key, completely bypassing password verification. An attacker can craft a v5-format file with a raw attacker-controlled post-quantum private key, set aead_binding to false, and pre-compute content hashes, resulting in a file that decrypts under any password while displaying "integrity verified". The vulnerability requires no network access and affects versions before 1.4.9. The fix (released in 1.4.9) default-denies any file with an unencrypted embedded PQC private key before any decryption occurs; legitimate legacy files can be read by explicitly passing allow_unencrypted_pqc_key=True.

## Affected products

- jahlives openssl_encrypt before 1.4.9

## Identifiers

- CVE-2026-81703
- PYSEC-2026-3779

## Timeline

- 2026-08-27: disclosed
- 2026-08-27: patched: Version 1.4.9 released

## References

- [https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-qqfq-g2cv-j7v3](https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-qqfq-g2cv-j7v3)
- [https://www.vulncheck.com/advisories/openssl-encrypt-before-1.4.9-authentication-bypass-via-unencrypted-pqc-key](https://www.vulncheck.com/advisories/openssl-encrypt-before-1.4.9-authentication-bypass-via-unencrypted-pqc-key)

## Related threats

- [openssl_encrypt KDF cost parameter validation bypass](https://junglewise.ai/threats/cve-2026-81721-openssl-encrypt-kdf-cost-parameter-validation-bypass)
- [openssl_encrypt memory exhaustion in identity file protection block](https://junglewise.ai/threats/cve-2026-81720-openssl-encrypt-memory-exhaustion-in-identity-file-protection)
- [openssl_encrypt arbitrary code execution via plugin signature bypass](https://junglewise.ai/threats/cve-2026-81719-openssl-encrypt-arbitrary-code-execution-via-plugin-signature)
- [openssl_encrypt weak PBKDF2 parameters in keyfile encryption](https://junglewise.ai/threats/cve-2026-81718-openssl-encrypt-weak-pbkdf2-parameters-in-keyfile-encryption)
- [openssl_encrypt USB drive integrity bypass with fixed KDF salt](https://junglewise.ai/threats/cve-2026-81717-openssl-encrypt-usb-drive-integrity-bypass-with-fixed-kdf-salt)