VDB-436708 · CVE-2026-103645 · GCVE-0-2026-103645

Qt QTextCodec fromUnicode/toUnicode integer overflow

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 was found in Qt. It has been declared as critical. This affects the function fromUnicode/toUnicode of the component QTextCodec. Executing a manipulation can lead to integer overflow. This vulnerability appears as CVE-2026-103645. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability classified as critical was found in Qt (version now known). This vulnerability affects the function fromUnicode/toUnicode of the component QTextCodec. The manipulation with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is CWE-190. The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

An integer overflow vulnerability in the Qt QTextCodec fromUnicode() and toUnicode() functionality of the Qt 5 Core Compatibility APIs module (Qt 6) and the Qt Core module (Qt 5). Only builds where Qt is compiled with ICU support are affected.

The advisory is shared for download at qt.io. This vulnerability was named CVE-2026-103645 since 10/01/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

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

Name

License

open-source

CPE 2.3info

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CPE 2.2info

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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

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

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined
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

10/01/2026 CVE reserved
11/13/2026 +43 days Advisory disclosed
11/13/2026 +0 days VulDB entry created
11/13/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: qt.io
Status: Confirmed

CNA: Qt
CVE: CVE-2026-103645 (🔒)

GCVE (CVE): GCVE-0-2026-103645
GCVE (VulDB): GCVE-100-436708

Entryinfo

Created: 11/13/2026 11:03
Changes: 11/13/2026 11:03 (66)
Complete: 🔍
Cache ID: 216::103