CVE-2026-39892 — cryptography
CVE-2026-39892 is a Buffer Overflow vulnerability in cryptography. A fix is available for cryptography — see the affected versions and patch details below.
cryptography has a buffer overflow if non-contiguous buffers were passed to APIs
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-39892.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
cryptographyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. From 45.0.0 to before 46.0.7, if a non-contiguous buffer was passed to APIs which accepted Python buffers (e.g. Hash.update()), this could lead to buffer overflows. This vulnerability is fixed in 46.0.7.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cryptography | ≥ 45.0.0&&< 46.0.7 | 46.0.7pip install --upgrade 'cryptography==46.0.7' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cryptography, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cryptography to 46.0.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39892 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-39892 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-39892. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
In default configurations Red Hat products isolate service processes from total system access. Should an attacker be able to exploit this vulnerability their impact will be limited to that service account and they will not have access to the broader system.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Automation Platform 2.5 for RHEL 8 | automation-controller-0:4.6.29-2.el8ap | RHSA-2026:24761 |
| Red Hat Ansible Automation Platform 2.6 for RHEL 9 | automation-controller-0:4.7.12-1.el9ap | RHSA-2026:24762 |
| Red Hat AI Inference Server 3.3 | rhaiis/vllm-rocm-rhel9:1782353093 | RHSA-2026:30088 |
| Red Hat AI Inference Server 3.3 | rhaiis/vllm-cuda-rhel9:1782352847 | RHSA-2026:30089 |
| Red Hat Ansible Automation Platform 2.6 | ansible-automation-platform-26/controller-rhel9:1779762270 | RHSA-2026:24866 |
| Red Hat Discovery 2 | discovery/discovery-server-rhel9:1779395228 | RHSA-2026:20338 |
| Red Hat Discovery 2 | discovery/discovery-server-rhel9:1779395228 | RHSA-2026:26068 |
| Red Hat Enterprise Linux AI 3.3 | rhelai3/bootc-rocm-rhel9:1784670204 | RHSA-2026:43651 |
Frequently Asked Questions
Is CVE-2026-39892 in your dependencies?
O3 Security finds CVE-2026-39892 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.