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Fencer Vulns
high 7.5

CVE-2018-6594 json

Pycrypto generates weak key parameters

published 2018-02-03 8 y ago modified 2026-06-17 4 mo ago also GHSA-6528-wvf6-f6qg , PYSEC-2018-97 , EUVD-2018-0119

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

lib/Crypto/PublicKey/ElGamal.py in PyCrypto through 2.6.1 generates weak ElGamal key parameters, 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 PyCrypto's ElGamal implementation.

Patch / fix

  • pycryptodome Debian 14, Debian 13, Debian 12 3.4.11-1

debian advisories DEBIAN-CVE-2018-6594

  • pycryptodome Ubuntu 18.04 LTS 3.4.7-1ubuntu1
  • python-crypto Ubuntu 14.04 LTS 2.6.1-4ubuntu0.3
  • python-crypto Ubuntu 16.04 LTS 2.6.1-6ubuntu0.16.04.3
  • python-crypto Ubuntu 18.04 LTS 2.6.1-8ubuntu2

ubuntu advisories UBUNTU-CVE-2018-6594

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-6594 updated cvss 5.3

python-crypto: Weak ElGamal key parameters in PublicKey/ElGamal.py allow attackers to obtain sensitive information by reading ciphertext

  • Red Hat CloudForms Management Engine 5 python-crypto, python2-crypto Red Hat Ceph Storage 1.3 python-crypto Red Hat Ceph Storage 2 python-crypto Red Hat Ceph Storage 3 python-crypto, python2-crypto Red Hat Enterprise Linux 6 python-crypto Red Hat Enterprise Linux 7 python-crypto
    +12 more products
    Red Hat Enterprise Linux OpenStack Platform 6 (Juno) python-crypto Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) python-crypto, python2-crypto Red Hat OpenShift Enterprise 3 python-crypto, python2-crypto Red Hat OpenStack Platform 8 (Liberty) python-crypto, python2-crypto Red Hat OpenStack Platform 9 (Mitaka) python-crypto, python2-crypto Red Hat OpenStack Platform 10 (Newton) python-crypto, python2-crypto Red Hat OpenStack Platform 11 (Ocata) python-crypto Red Hat OpenStack Platform 12 (Pike) python2-crypto Red Hat OpenStack Platform 13 (Queens) python2-crypto Red Hat Storage 3 python-crypto, python2-crypto Red Hat Storage Console 2 python-crypto Red Hat Virtualization 4 python-crypto
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.03% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/dlitz/pycrypto/issues/253 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi pycrypto
<=2.6.1
all versions
 no fix listed

Classification

Weakness
  • CWE-326 Inadequate Encryption Strength

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.