Ubuntu.comUB:CVE-2021-40528CVE-2021-40528
5 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:N/A:N
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
0.002 Low
EPSS
Percentile
61.2%
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.
Bugs
Notes
| Author | Note |
|---|---|
| mdeslaur | The commits below reference CVE-2021-33560, but they appear to actually be for this CVE, which was issued later. The original CVE was switched later on to the exponent blinding issue instead. |
| OS | Version | Architecture | Package | Version | Filename |
|---|---|---|---|---|---|
| ubuntu | 18.04 | noarch | libgcrypt20 | < 1.8.1-4ubuntu1.3 | UNKNOWN |
| ubuntu | 20.04 | noarch | libgcrypt20 | < 1.8.5-5ubuntu1.1 | UNKNOWN |
| ubuntu | 21.04 | noarch | libgcrypt20 | < 1.8.7-2ubuntu2.1 | UNKNOWN |
| ubuntu | 21.10 | noarch | libgcrypt20 | < 1.8.7-5ubuntu2 | UNKNOWN |
| ubuntu | 22.04 | noarch | libgcrypt20 | < 1.8.7-5ubuntu2 | UNKNOWN |
| ubuntu | 22.10 | noarch | libgcrypt20 | < 1.8.7-5ubuntu2 | UNKNOWN |
| ubuntu | 23.04 | noarch | libgcrypt20 | < 1.8.7-5ubuntu2 | UNKNOWN |
| ubuntu | 23.10 | noarch | libgcrypt20 | < 1.8.7-5ubuntu2 | UNKNOWN |
| ubuntu | 24.04 | noarch | libgcrypt20 | < 1.8.7-5ubuntu2 | UNKNOWN |
| ubuntu | 16.04 | noarch | libgcrypt20 | < 1.6.5-2ubuntu0.6+esm1 | UNKNOWN |
References
eprint.iacr.org/2021/923
ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1
ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2
launchpad.net/bugs/cve/CVE-2021-40528
nvd.nist.gov/vuln/detail/CVE-2021-40528
security-tracker.debian.org/tracker/CVE-2021-40528
ubuntu.com/security/notices/USN-5080-1
ubuntu.com/security/notices/USN-5080-2
www.cve.org/CVERecord?id=CVE-2021-40528
Related
5 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:N/A:N
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
0.002 Low
EPSS
Percentile
61.2%