CVE-2016-9243

CVE-2016-9243 is a high-severity vulnerability in Cryptography.io Cryptography with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

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

Frequently asked questions

What is CVE-2016-9243?
HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.
How severe is CVE-2016-9243?
CVE-2016-9243 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2016-9243 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-9243?
CVE-2016-9243 primarily affects Cryptography.io Cryptography. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-9243?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-9243 published?
CVE-2016-9243 was published on 2017-03-27 and last updated on 2026-06-17.

References

Affected products (6)

More vulnerabilities in Cryptography.io Cryptography

All CVEs affecting Cryptography.io Cryptography →