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🛡️ CVE-2026-39892 — cryptography

🔴 CVSS 9.8 — Critical ✅ No Known Exploit CWE-119 OSV
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Cryptography vulnerable to buffer overflow if non-contiguous buffers were passed to APIs

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:

```python

h = Hash(SHA256())

b.update(buf[::-1])

```

would read past the end of the buffer on Python >3.11

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-39892 is classified as CWE-119: Improper Restriction of Operations within Memory Buffer Bounds. A read or write is performed without confirming it stays inside the allocated buffer, corrupting adjacent memory.

Affected software

CVE-2026-39892 is recorded against 1 package.

  • cryptography (from 45.0.0 up to 46.0.7)

Timeline and source

Published on 8 April 2026 and last revised on 17 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

www.openwall.com (Advisory)
github.com (Advisory)

Other advisories for this package

cryptography has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-119: Improper Restriction of Operations within Memory Buffer Bounds) in other software:

CVE-2026-39892 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity CRITICAL
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-119
Public Exploit ✅ No
Source OSV
Published 2026-04-08
Updated 2026-08-20
Modified 2026-08-17
Fix URL N/A

Affected Packages

Software From version Fixed in
cryptography 45.0.0 46.0.7

Exploit Protection

Are you running cryptography?

CVE-2026-39892 carries CVSS 9.8 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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