CVE-2016-9243

high
Published 2017-03-27 · Modified 2023-11-08
CVSS v3
7.5
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS v2
5.0
VIR risk
7.5

Description

HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.

Predictions

Exploit likelihood
83%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2016-9243

vendor Authored 2026-05-27

Vendor advisory: secalert@redhat.com — https://github.com/pyca/cryptography/commit/b924696b2e8731f39696584d12cceeb3aeb2d874

vendor Authored 2026-05-27

Vendor advisory: secalert@redhat.com — https://cryptography.io/en/latest/changelog

vendor Authored 2026-05-27

Vendor advisory: secalert@redhat.com — http://www.openwall.com/lists/oss-security/2016/11/09/2

OS impact

OSVersionStatusFixed in
ubuntu ubuntu16.04affected
ubuntu ubuntu16.10affected
fedora fedora23affected
fedora fedora24affected
fedora fedora25affected
debian debianbookwormfixed1.5.3-1
debian debianbullseyefixed1.5.3-1
debian debianforkyfixed1.5.3-1
debian debiansidfixed1.5.3-1
debian debiantrixiefixed1.5.3-1

Package impact

EcosystemPackageVulnerableFixed
python PyPIcryptography<1.5.31.5.3
python PyPIcryptography<b924696b2e8731f39696584d12cceeb3aeb2d874||<1.5.3b924696b2e8731f39696584d12cceeb3aeb2d874

Application impact

VendorProductVersionsFixed
cryptography.iocryptography{"endIncluding":"1.5.2"}

References

Verify integrity in audit chain (admin only). AS-IS.