CVE-2021-37587Public exploitNetwork attack vector

Unauthorized decryption via exploitable ABE algebra

Published Jul 27, 2021 · Updated Aug 4, 2024

Broken cryptography in Charm 0.43 allows authenticated users to decrypt DAC-MACS or MA-ABE-YJ14 ciphertexts outside their attributes. The scheme implementations preserve exploitable algebraic dependencies, allowing valid key material to defeat the ciphertext access policy and recover plaintext. DAC-MACS requires one registered user; the documented YJ14 attack also requires control of one attribute authority, and the consequence is unauthorized data disclosure.

CVSS severity6.5
Medium
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Broken cryptography in Charm 0.43 allows authenticated users to decrypt DAC-MACS or MA-ABE-YJ14 ciphertexts outside their attributes. The scheme implementations preserve exploitable algebraic dependencies, allowing valid key material to defeat the ciphertext access policy and recover plaintext. DAC-MACS requires one registered user; the documented YJ14 attack also requires control of one attribute authority, and the consequence is unauthorized data disclosure.

The record

CVE
CVE-2021-37587
Published
Jul 27, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-327
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo