CVE-2023-49083Public exploitNetwork attack vector

Application crash via certificate-free PKCS#7 SignedData dereference

Published Nov 29, 2023 · Updated Dec 18, 2025

NULL pointer dereference in Python Cryptographic Authority cryptography 3.1 through 41.0.5 allows remote attackers to crash applications. When a certificate-free PKCS#7 SignedData blob reaches load_pem_pkcs7_certificates or load_der_pkcs7_certificates, _load_pkcs7_certificates dereferences p7.d.sign without first checking whether OpenSSL returned NULL. Exploitation requires an application to pass attacker-controlled PKCS#7 data to either loader; the resulting segmentation fault terminates that process without affecting confidentiality or integrity.

CVSS severity5.9
Medium
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Python Cryptographic Authority cryptography 3.1 through 41.0.5 allows remote attackers to crash applications. When a certificate-free PKCS#7 SignedData blob reaches load_pem_pkcs7_certificates or load_der_pkcs7_certificates, _load_pkcs7_certificates dereferences p7.d.sign without first checking whether OpenSSL returned NULL. Exploitation requires an application to pass attacker-controlled PKCS#7 data to either loader; the resulting segmentation fault terminates that process without affecting confidentiality or integrity.

The record

CVE
CVE-2023-49083
Published
Nov 29, 2023
Updated
Dec 18, 2025
Vendor
Python Cryptographic Authority
Product
cryptography
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 18, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.1, < 41.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Python Cryptographic Authority · cryptographyversion=>= 3.1, < 41.0.6

Published CVSS scores

5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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