CVE-2016-9243: canonical ubuntu_linux
Vulnerability summary
CVE-2016-9243 is a high (CVSS 7.5) vulnerability in canonical ubuntu_linux. EPSS estimates a 3.46% chance of exploitation in the next 30 days, higher than 89% of scored vulnerabilities.
Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 3% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Timeline
- 27-03-2017PublishedVulnerability first disclosed.
- 06-08-2024Last modifiedVulnerability information updated.
Description
HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.
CVSS metrics
7 scores · 4 sources · 4 versions- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS trend
Probability
3.46%
Chance of exploitation in the next 30 days
Percentile
89%
Versus all other CVEs
30-day change
No change 0.00 pp
From 3.46% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Canonical1 product
- ubuntu_linuxEOL16.04 | 16.10
Cryptography.io1 product
- cryptography≤ 1.5.2
Debian1 product
- python-cryptography< 1.5.3-1
Fedoraproject1 product
- fedoraEOL23 | 24 | 25
Mageia1 product
- python-cryptography< 1.0.2-1.1.mga5
PyPI1 product
- cryptography< b924696b2e8731f39696584d12cceeb3aeb2d874 | < 1.5.3
Ubuntu1 product
- python-cryptography< 1.2.3-1ubuntu0.1
7 vendors · 7 products
References
32 links- github.com/pyca/cryptography/commit/b924696b2e8731f39696584d12cceeb3aeb2d874X Refsource CONFIRMPatchThird Party AdvisoryWEBFIX
- github.com/pyca/cryptography/issues/3211X Refsource CONFIRMIssue TrackingThird Party AdvisoryWEBREPORT
Show all 32 references
- github.com/pyca/cryptographyPACKAGE
