CVE-2021-31239Public exploit

CLI crash via unchecked appendvfs cleanup

Published May 9, 2023 · Updated May 5, 2025

A NULL-pointer dereference in SQLite CLI 3.35.4 allows local users with unrestricted shell access to crash the process. In appendvfs apndOpen, a failed base-VFS open leaves pBaseFile->pMethods unset, yet error cleanup calls its xClose method. The extension is outside the core library, and reachability requires CLI control of an append operation against a nonexistent file.

CVSS severity7.5
High
EPSS probability2.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A NULL-pointer dereference in SQLite CLI 3.35.4 allows local users with unrestricted shell access to crash the process. In appendvfs apndOpen, a failed base-VFS open leaves pBaseFile->pMethods unset, yet error cleanup calls its xClose method. The extension is outside the core library, and reachability requires CLI control of an append operation against a nonexistent file.

The record

CVE
CVE-2021-31239
Published
May 9, 2023
Updated
May 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 9, 2023CVE publishedPublication date reported by the CVE source.
  2. May 5, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS: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.

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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)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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