CVE-2026-39892: Cryptography vulnerable to buffer overflow if non-contiguous buffers were passed to APIs
(updated )
If a non-contiguous buffer was passed to APIs which accepted Python buffers (e.g. Hash.update()), this could lead to buffer overflows. For example:
h = Hash(SHA256())
b.update(buf[::-1])
would read past the end of the buffer on Python >3.11
References
- access.redhat.com/errata/RHSA-2026:19375
- access.redhat.com/errata/RHSA-2026:20338
- access.redhat.com/errata/RHSA-2026:21017
- access.redhat.com/errata/RHSA-2026:22465
- access.redhat.com/errata/RHSA-2026:22629
- access.redhat.com/errata/RHSA-2026:22840
- access.redhat.com/errata/RHSA-2026:23361
- access.redhat.com/errata/RHSA-2026:24483
- access.redhat.com/errata/RHSA-2026:24761
- access.redhat.com/errata/RHSA-2026:24762
- access.redhat.com/errata/RHSA-2026:24853
- access.redhat.com/errata/RHSA-2026:24866
- access.redhat.com/errata/RHSA-2026:24977
- access.redhat.com/errata/RHSA-2026:30088
- access.redhat.com/errata/RHSA-2026:30089
- access.redhat.com/errata/RHSA-2026:37275
- access.redhat.com/errata/RHSA-2026:42644
- access.redhat.com/errata/RHSA-2026:43651
- access.redhat.com/errata/RHSA-2026:43670
- access.redhat.com/errata/RHSA-2026:43851
- access.redhat.com/errata/RHSA-2026:43853
- access.redhat.com/errata/RHSA-2026:43854
- access.redhat.com/errata/RHSA-2026:43855
- access.redhat.com/errata/RHSA-2026:46956
- access.redhat.com/errata/RHSA-2026:7295
- access.redhat.com/security/cve/CVE-2026-39892
- bugzilla.redhat.com/show_bug.cgi?id=2456735
- github.com/advisories/GHSA-p423-j2cm-9vmq
- github.com/pyca/cryptography/commit/622d672e429a7cff836a23c5903683dbec1901f5
- github.com/pyca/cryptography/commit/c09d38ae52de7d95fe683b7a7c496f5751616f27
- github.com/pyca/cryptography/security/advisories/GHSA-p423-j2cm-9vmq
- github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-36.yaml
- nvd.nist.gov/vuln/detail/CVE-2026-39892
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39892.json
Code Behaviors & Features
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