CVE-2021-40529

Severity Score

5.9

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, 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.

Una implementación de ElGamal en Botan versiones hasta 2.18.1, tal y como se usa en Thunderbird y otros productos, permite una recuperación de texto plano porque, durante la interacción entre dos bibliotecas criptográficas, una determinada combinación peligrosa del primo definido por la clave pública del receptor, el generador definido por la clave pública del receptor y los exponentes efímeros del emisor puede conllevar a un ataque de configuración cruzada contra OpenPGP.

*Credits: N/A

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Attack Vector

Network

Attack Complexity

High

Authentication

None

Confidentiality

Partial

Integrity

None

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-09-06 CVE Reserved
2021-09-06 CVE Published
2024-08-04 CVE Updated
2024-08-04 First Exploit
2024-11-07 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-327: Use of a Broken or Risky Cryptographic Algorithm

CAPEC

References (7)

URL	Tag	Source
https://eprint.iacr.org/2021/923	Technical Description
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1	Third Party Advisory

URL	Date	SRC
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2	2024-08-04

URL	Date	SRC
https://github.com/randombit/botan/pull/2790	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB	2023-11-07
https://security.gentoo.org/glsa/202208-14	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Botan Project Search vendor "Botan Project"		Botan Search vendor "Botan Project" for product "Botan"				<= 2.18.1 Search vendor "Botan Project" for product "Botan" and version " <= 2.18.1"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				34 Search vendor "Fedoraproject" for product "Fedora" and version "34"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				35 Search vendor "Fedoraproject" for product "Fedora" and version "35"		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				< 91.12.0 Search vendor "Mozilla" for product "Thunderbird" and version " < 91.12.0"		-		Affected