CVE-2021-41497Public exploitNetwork attack vector

Python process crash via unchecked hash-bucket width

Published Dec 17, 2021 · Updated Aug 4, 2024

Null dereference in RaRe-Technologies bounter 1.01 and 1.10 allows remote attackers to crash a Python process via an oversized hash-bucket width. CMS_Conservative_init accepts the width without validation, permits calloc to fail, and leaves a null table entry that CMS_Conservative_increment_obj dereferences. Exploitation requires a calling application to pass attacker-controlled width into the Python extension and interrupts that process without disclosing or modifying data.

CVSS severity7.5
High
EPSS probability1.04%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Null dereference in RaRe-Technologies bounter 1.01 and 1.10 allows remote attackers to crash a Python process via an oversized hash-bucket width. CMS_Conservative_init accepts the width without validation, permits calloc to fail, and leaves a null table entry that CMS_Conservative_increment_obj dereferences. Exploitation requires a calling application to pass attacker-controlled width into the Python extension and interrupts that process without disclosing or modifying data.

The record

CVE
CVE-2021-41497
Published
Dec 17, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo