LiveActive security incident?Get immediate response
CVE Record

CVE-2026-39892: cryptography has a buffer overflow if non-contiguous buffers were passed to APIs

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.

HighCVSS 7.3Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-39892 affects the Python cryptography package. Versions 45.0.0 through 46.0.6 can overflow memory when certain non-contiguous buffers are passed into buffer-accepting APIs. Because cryptography is widely embedded in Python software, exposure depends on dependency versions and whether applications pass those buffer types.

Executive priority

Treat as high priority for patch management, especially in internet-facing Python services and vendor-managed platforms. There is a fixed upstream release, and no active exploitation is cited in the bundle, so rapid normal remediation is appropriate unless local exposure is confirmed.

Technical view

The flaw is a buffer overflow in pyca cryptography when non-contiguous Python buffers are supplied to APIs accepting Python buffers, such as Hash.update(). The affected range is >=45.0.0 and <46.0.7. It is classified as CWE-119 and CWE-131 with CVSS 3.1 score 7.3.

Likely exposure

Most likely exposure is Python applications, services, containers, and vendor packages that bundle cryptography versions 45.0.0 through 46.0.6. Direct exposure requires vulnerable API usage with non-contiguous buffers; the bundle does not identify specific downstream applications beyond Red Hat advisories.

Exploitation context

The source bundle marks KEV as false and provides no cited evidence of active exploitation. The CVSS vector indicates network attack vector, low complexity, no privileges, and no user interaction, but practical exploitability depends on application-specific buffer handling.

Researcher notes

Focus validation on the affected version window and API paths accepting Python buffers. The public bundle names the vulnerable condition but does not provide downstream exploit evidence, product-specific reachability, or detailed trigger conditions beyond non-contiguous buffers.

Mitigation direction

  • Upgrade pyca cryptography to 46.0.7 or later.
  • Apply relevant Red Hat security advisories where cryptography is vendor-managed.
  • Inventory Python lockfiles, images, and system packages for affected versions.
  • Check vendor guidance for bundled or appliance-delivered Python components.
  • Prioritize externally reachable services handling untrusted binary or buffer-like input.

Validation and detection

  • Confirm installed cryptography versions are outside >=45.0.0 and <46.0.7.
  • Review dependency manifests, SBOMs, and container layers for cryptography.
  • Identify code paths passing memoryview, NumPy, or other buffer objects into cryptography APIs.
  • Verify Red Hat errata applicability for managed platforms and packages.
  • Monitor vendor advisories for downstream product-specific exposure statements.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-119: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-131: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-39892 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.3 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
3ADP providers
22Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.3CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4redhat-SADP
6.9CVSS 4.0MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

6.9Medium
CVSS 4.0 vector shape for CVE-2026-39892Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPcryptography: Cryptography: Buffer overflow via non-contiguous buffer in API
other:Red Hat severity ratingcvssV3_1
  • 2026-04-08T22:00:59.416Z: Reported to Red Hat.
  • 2026-04-08T20:49:41.967Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
pycacryptography>= 45.0.0, < 46.0.7Listed
Weakness

CWE details

CWE-119CWE-131

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.