VDB-248636 · CVE-2023-51598 · ZDI-23-1855

Hancom Office Word DOC File Parser use after free

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.3	$0-$5k	0.00

Summaryinfo

A vulnerability labeled as critical has been found in Hancom Office. This vulnerability affects unknown code of the component Word DOC File Parser. Such manipulation leads to use after free. This vulnerability is documented as CVE-2023-51598. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Hancom Office (the affected version unknown). Affected by this issue is an unknown part of the component Word DOC File Parser. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Hancom Office Word DOC File Parsing Use-After-Free Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Hancom Office Word. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of DOC files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-20384.

The weakness was released 12/21/2023 as ZDI-23-1855. The advisory is shared for download at zerodayinitiative.com. This vulnerability is handled as CVE-2023-51598 since 12/20/2023. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/14/2025).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Hancom

Name

Office

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 7.3

VulDB Base Score: 6.3
VulDB Temp Score: 6.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 8.8
NVD Vector: 🔍

CNA Base Score: 7.0
CNA Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

12/20/2023 🔍
12/21/2023 +1 days 🔍
12/21/2023 +0 days 🔍
08/14/2025 +602 days 🔍

Sourcesinfo

Advisory: ZDI-23-1855
Status: Not defined

CVE: CVE-2023-51598 (🔍)
GCVE (CVE): GCVE-0-2023-51598
GCVE (VulDB): GCVE-100-248636

Entryinfo

Created: 12/21/2023 07:39
Updated: 08/14/2025 03:59
Changes: 12/21/2023 07:39 (36), 08/14/2025 03:59 (37)
Complete: 🔍
Cache ID: 216::103