5.9
MEDIUM
CVE-2021-40528
Libgcrypt ElGamal Plaintext Recovery Vulnerability
Description

The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.

INFO

Published Date :

Sept. 6, 2021, 7:15 p.m.

Last Modified :

Nov. 7, 2023, 3:38 a.m.

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

2.2
Public PoC/Exploit Available at Github

CVE-2021-40528 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2021-40528 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Gnupg libgcrypt
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-40528.

URL Resource
https://eprint.iacr.org/2021/923 Technical Description Third Party Advisory
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 Third Party Advisory
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 Exploit Third Party Advisory
https://security.gentoo.org/glsa/202210-13 Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

a test code repository

Dockerfile HCL

Updated: 1 year, 6 months ago
1 stars 0 fork 0 watcher
Born at : Sept. 29, 2021, 6:37 p.m. This repo has been linked 13 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-40528 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-40528 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320 [No types assigned]
    Removed Reference MITRE https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=3462280f2e23e16adf3ed5176e0f2413d8861320
  • Modified Analysis by [email protected]

    Dec. 07, 2022

    Action Type Old Value New Value
    Changed Reference Type https://security.gentoo.org/glsa/202210-13 No Types Assigned https://security.gentoo.org/glsa/202210-13 Third Party Advisory
  • CVE Modified by [email protected]

    Oct. 31, 2022

    Action Type Old Value New Value
    Added Reference https://security.gentoo.org/glsa/202210-13 [No Types Assigned]
  • Modified Analysis by [email protected]

    Nov. 29, 2021

    Action Type Old Value New Value
    Changed Reference Type https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=3462280f2e23e16adf3ed5176e0f2413d8861320 No Types Assigned https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=3462280f2e23e16adf3ed5176e0f2413d8861320 Mailing List, Patch, Third Party Advisory
  • CVE Modified by [email protected]

    Nov. 17, 2021

    Action Type Old Value New Value
    Added Reference https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=3462280f2e23e16adf3ed5176e0f2413d8861320 [No Types Assigned]
  • Initial Analysis by [email protected]

    Sep. 13, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:H/Au:N/C:P/I:N/A:N)
    Added CVSS V3.1 NIST AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://eprint.iacr.org/2021/923 No Types Assigned https://eprint.iacr.org/2021/923 Technical Description, Third Party Advisory
    Changed Reference Type https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 No Types Assigned https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 Third Party Advisory
    Changed Reference Type https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 No Types Assigned https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 Exploit, Third Party Advisory
    Added CWE NIST CWE-327
    Added CPE Configuration OR *cpe:2.3:a:gnupg:libgcrypt:*:*:*:*:*:*:*:* versions up to (excluding) 1.9.4
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-40528 is associated with the following CWEs:

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.20 }} 0.02%

score

0.57380

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability