CVE-2018-6829
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly...
CVE-2018-6829 is a high vulnerability (CVSS 7.5) in Gnupg Libgcrypt, published February 7, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.78%, the 78th percentile. Fixed in libgcrypt20 1.10.1-3.root.io.2.
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
- Record
CVE-2018-6829- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:P/I:N/A:N - Weakness
- CWE-327
- Updated
- 2026-11-02
CVE List No score
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
- Record
CVE-2018-6829- Updated
- 2026-11-02
EUVDEUVD-2018-18576 No score
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
- Record
EUVD-2018-18576- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-wcf7-2f92-j5mv
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly...
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
- Record
GHSA-wcf7-2f92-j5mv- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-327
- Updated
- 2026-11-02
OSV
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
- Record
CVE-2018-6829- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVDEBIAN-CVE-2018-6829
cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.
- Record
DEBIAN-CVE-2018-6829- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVROOT-OS-DEBIAN-12-CVE-2018-6829 No score
CVE-2018-6829 in libgcrypt20 - Patched by Root
Root has patched CVE-2018-6829 in the libgcrypt20 package for Root:Debian:12. Multiple fixed versions available.
- Record
ROOT-OS-DEBIAN-12-CVE-2018-6829- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
gnupg1Debian:12 |
All versions, plus listed versions 1.4.23-1.11.4.23-21.4.23-3 |
None known |
gnupg1Debian:13 |
All versions, plus listed versions 1.4.23-3 |
None known |
gnupg1Debian:14 |
All versions, plus listed versions 1.4.23-3 |
None known |
libgcrypt20Debian:12 |
All versions, plus listed versions 1.10.1-31.10.1-3+deb12u11.10.2-11.10.2-21.10.2-2+loong64 Show 26 moreShow less1.10.2-31.10.3-11.10.3-21.10.3-31.11.0+git20250114-11.11.0-11.11.0-21.11.0-31.11.0-41.11.0-51.11.0-61.11.0-71.11.0~beta450-11.11.1-11.11.2-11.11.2-21.11.2-31.12.0-11.12.0-21.12.1-11.12.1-21.12.2-11.12.3-11.12.3-21.12.4-11.12.4-2 |
None known |
libgcrypt20Debian:13 |
All versions, plus listed versions 1.11.0+git20250114-11.11.0-71.11.0-7+deb13u11.11.1-11.11.2-1 Show 11 moreShow less1.11.2-21.11.2-31.12.0-11.12.0-21.12.1-11.12.1-21.12.2-11.12.3-11.12.3-21.12.4-11.12.4-2 |
None known |
libgcrypt20Debian:14 |
All versions, plus listed versions 1.11.0+git20250114-11.11.0-71.11.1-11.11.2-11.11.2-2 Show 10 moreShow less1.11.2-31.12.0-11.12.0-21.12.1-11.12.1-21.12.2-11.12.3-11.12.3-21.12.4-11.12.4-2 |
None known |
libgcrypt20Root:Debian:12 |
before 1.10.1-3.root.io.2 | 1.10.1-3.root.io.21.10.1-3.root.io.31.10.1-3.root.io.41.10.1-3+deb12u1.aikido.5 |
rootio-libgcrypt20Root:Debian:12 |
before 1.10.1-3.root.io.2 | 1.10.1-3.root.io.21.10.1-3.root.io.31.10.1-3.root.io.41.10.1-3+deb12u1.aikido.5 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
github.com/weikengchen/attack-on-libgcrypt-elgamal/wiki
lists.gnupg.org/pipermail/gcrypt-devel/2018-February/004394.html
oracle.com/security-alerts/cpujan2020.html
nvd.nist.gov/vuln/detail/CVE-2018-6829
security-tracker.debian.org/tracker/CVE-2018-6829