CVE catalog

CVE-2021-40530

libcrypto++: CVE-2021-40530

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published: Jul 20, 2021, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 1.16% · Oct 27, 2026

The ElGamal implementation in Crypto++ through 8.5 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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	libcrypto++	sid	`8.9.0-3`	fixed
Debian	libcrypto++	forky	`8.9.0-3`	fixed
Debian	libcrypto++	trixie	`8.9.0-2`	fixed
Debian	libcrypto++	bookworm	`8.7.0+git220824-1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	libcrypto++	source	sid	`8.6.0-1`	not yet assigned	Not reported	[993841]
Debian	libcrypto++	source	forky	`8.6.0-1`	not yet assigned	Not reported	[993841]
Debian	libcrypto++	source	trixie	`8.6.0-1`	not yet assigned	Not reported	[993841]
Debian	libcrypto++	source	bookworm	`8.6.0-1`	not yet assigned	Not reported	[993841]

[Debian bug #993841]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libcrypto++8]Fixed
Source package: [libcrypto++]
Details (2)
- 8.7.0+git220824-1 · amd64 · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
- 8.7.0+git220824-1 · arm64 · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
[libcrypto++-dev]Fixed
Source package: [libcrypto++]
Details (2)
- 8.7.0+git220824-1 · amd64 · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
- 8.7.0+git220824-1 · arm64 · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
[libcrypto++-doc]Fixed
Source package: [libcrypto++]
Details (2)
- 8.7.0+git220824-1 · all · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
- 8.7.0+git220824-1 · all · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
[libcrypto++-utils]Fixed
Source package: [libcrypto++]
Details (2)
- 8.7.0+git220824-1 · amd64 · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12
- 8.7.0+git220824-1 · arm64 · bookworm
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · bookworm; dsa · libcrypto++ · debian · 12

[Debian 13 (Trixie)]

[libcrypto++8t64]Fixed
Source package: [libcrypto++]
Details (2)
- 8.9.0-2 · amd64 · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
- 8.9.0-2 · arm64 · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
[libcrypto++-dev]Fixed
Source package: [libcrypto++]
Details (2)
- 8.9.0-2 · amd64 · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
- 8.9.0-2 · arm64 · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
[libcrypto++-doc]Fixed
Source package: [libcrypto++]
Details (2)
- 8.9.0-2 · all · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
- 8.9.0-2 · all · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
[libcrypto++-utils]Fixed
Source package: [libcrypto++]
Details (2)
- 8.9.0-2 · amd64 · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13
- 8.9.0-2 · arm64 · trixie
  Fixed · Fixed: 8.6.0-1
  dsa · libcrypto++ · debian · 13

Observed: Oct 23, 2026, 6:02:28 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]