CVE-2021-42613Public exploit

Document-processor crash via double-free cleanup

Published May 24, 2022 · Updated Aug 4, 2024

Double free in cleanup_index in Halibut 1.2 allows attackers to crash the document processor via a crafted text document. The published analysis traces the second deallocation through free_word_list at index.c line 203 and identifies earlier frees of rsc.text in get_token as the root cause. Exploitation requires a user or automated workflow to process the malicious file with the WinHelp backend; the demonstrated consequence is an abort and service interruption.

CVSS severity7.8
High
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double free in cleanup_index in Halibut 1.2 allows attackers to crash the document processor via a crafted text document. The published analysis traces the second deallocation through free_word_list at index.c line 203 and identifies earlier frees of rsc.text in get_token as the root cause. Exploitation requires a user or automated workflow to process the malicious file with the WinHelp backend; the demonstrated consequence is an abort and service interruption.

The record

CVE
CVE-2021-42613
Published
May 24, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2022CVE 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

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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

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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-415Double Free
T1203Exploitation for Client Execution

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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