CVE-2021-33390Public exploit

Crash via freed tree-node dereference

Published Aug 22, 2023 · Updated Oct 3, 2024

Use-after-free in dpic 2021.04.10 allows attackers to crash the diagram processor by supplying a crafted pic input file. In deletestringbox() in dpic.y, deletetree() frees a heap node that the same processing path subsequently dereferences during a read. Exploitation requires processing the crafted file; the public reproducer demonstrates an AddressSanitizer abort but does not establish code execution.

CVSS severity9.8
Critical
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in dpic 2021.04.10 allows attackers to crash the diagram processor by supplying a crafted pic input file. In deletestringbox() in dpic.y, deletetree() frees a heap node that the same processing path subsequently dereferences during a read. Exploitation requires processing the crafted file; the public reproducer demonstrates an AddressSanitizer abort but does not establish code execution.

The record

CVE
CVE-2021-33390
Published
Aug 22, 2023
Updated
Oct 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 3, 2024Record 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1204.002Malicious File

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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