HIGH
python-cryptography: HKDF might return an empty byte-string
Published Mar 27, 2017
8.7
HIGHCVSS 4.0
EPSS 3.46%
Description
HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.
Affected products
No data.
Configuration 1
- ≤ 1.5.2
Configuration 2
OR
- 23
- 24
- 25
Configuration 3
OR
- 16.04
- 16.10
No data.
Red Hat Enterprise Linux 7
python-cryptography
Not affected
Red Hat Enterprise Linux OpenStack Platform 7 (Kilo)
python-cryptography
Will not fix
Red Hat OpenStack Platform 10 (Newton)
python-cryptography
Will not fix
Red Hat OpenStack Platform 8 (Liberty)
python-cryptography
Will not fix
Red Hat OpenStack Platform 9 (Mitaka)
python-cryptography
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | python-cryptography | Not affected | n/a |
| Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) | python-cryptography | Will not fix | n/a |
| Red Hat OpenStack Platform 10 (Newton) | python-cryptography | Will not fix | n/a |
| Red Hat OpenStack Platform 8 (Liberty) | python-cryptography | Will not fix | n/a |
| Red Hat OpenStack Platform 9 (Mitaka) | python-cryptography | Will not fix | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
8.7 HIGH GHSA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User Interaction None
Vulnerable System Confidentiality None
Vulnerable System Integrity High
Vulnerable System Availability None
Subsequent System Confidentiality None
Subsequent System Integrity None
Subsequent System Availability None
7.5 HIGH NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact High
Availability Impact None
7.5 HIGH GHSA
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact High
Availability Impact None
1 other source (Red Hat) ▾
4.8 MEDIUM Red Hat
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact Low
Integrity Impact Low
Availability Impact None
5.0 MEDIUM NVD
AV:N/AC:L/Au:N/C:N/I:P/A:N
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact Partial
Availability Impact None
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
3.46% 0.03464
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.03464
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (14 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 3.46% (0.03464) | 88.66th | v5 (v2026.06.15) |
| Jun 15, 2026 | 3.40% (0.03399) | 87.24th | v5 (v2026.06.15) |
| Mar 30, 2025 | 1.64% (0.01644) | 80.28th | v4 (v2025.03.14) |
| Mar 29, 2025 | 3.97% (0.03969) | 80.35th | v4 (v2025.03.14) |
| Mar 17, 2025 | 1.64% (0.01644) | 80.70th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.40% (0.00396) | 74.33th | v3 (v2023.03.01) |
| Mar 13, 2024 | 0.58% (0.00583) | 77.63th | v3 (v2023.03.01) |
| Nov 8, 2023 | 0.58% (0.00583) | 75.63th | v3 (v2023.03.01) |
| Jul 1, 2023 | 0.54% (0.00536) | 74.00th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.76% (0.00759) | 78.28th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.54% (0.01537) | 74.52th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.54% (0.01537) | 74.48th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.54% (0.01537) | 72.41th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.54% (0.01537) | 51.33th | v2 (v2022.01.01) |
References (19)
- http://www.openwall.com/lists/oss-security/2016/11/09/2 mailing-listx_refsource_MLISTMailing ListPatchVDB Entry
- http://www.securityfocus.com/bid/94216 vdb-entryx_refsource_BIDBroken LinkThird Party AdvisoryVDB Entry
- http://www.ubuntu.com/usn/USN-3138-1 vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2016-9243 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1393431 Issue Tracking
- https://cryptography.io/en/latest/changelog x_refsource_CONFIRMRelease NotesThird Party Advisory
- https://cryptography.io/en/latest/changelog/#v1-5-3
- https://github.com/advisories/GHSA-q3cj-2r34-2cwc Advisory
- https://github.com/pyca/cryptography/commit/b924696b2e8731f39696584d12cceeb3aeb2d874 x_refsource_CONFIRMPatchThird Party Advisory
- https://github.com/pyca/cryptography/issues/3211 x_refsource_CONFIRMIssue TrackingThird Party Advisory
- https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2017-8.yaml
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5R2ZOBMPWDFFHUZ6QOZZY36A6H5CGJXL vendor-advisoryx_refsource_FEDORAMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U23KDR2M2N7W2ZSREG63BVW7D4VC6CIZ vendor-advisoryx_refsource_FEDORAMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WQ5G7KHKZC4SI23JE7277KZXM57GEQKT vendor-advisoryx_refsource_FEDORAMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5R2ZOBMPWDFFHUZ6QOZZY36A6H5CGJXL
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U23KDR2M2N7W2ZSREG63BVW7D4VC6CIZ
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WQ5G7KHKZC4SI23JE7277KZXM57GEQKT
- https://nvd.nist.gov/vuln/detail/CVE-2016-9243
- https://www.cve.org/CVERecord?id=CVE-2016-9243
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner redhat
Published Mar 27, 2017
Updated Aug 6, 2024
Reserved Nov 9, 2016
Link CVE-2016-9243
CISA Vulnrichment
GHSA-Q3CJ-2R34-2CWC Updated n/a