CVE-2021-40528

MEDIUM
5.9
CVSS Score
Published: September 6, 2021 at 12:00 AM UTC
Updated: June 17, 2026 at 04:07 AM UTC
1 product affected across 1 vendorLibgcrypt

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Severity
MEDIUM5.9
Exploit prediction
EPSS 1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.9.4
Affected range stops below 1.9.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-327

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