sumatrapdfreader SumatraPDF up to 3.5 src/MobiDoc.cpp MobiDoc::ParseHeader heap-based overflow

Summaryinfo

A vulnerability described as problematic has been identified in sumatrapdfreader SumatraPDF up to 3.5. The affected element is the function MobiDoc::ParseHeader of the file src/MobiDoc.cpp. Executing a manipulation can lead to heap-based overflow. The identification of this vulnerability is CVE-2026-26054. The attack can only be executed locally. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in sumatrapdfreader SumatraPDF up to 3.5. It has been declared as problematic. This vulnerability affects the function MobiDoc::ParseHeader of the file src/MobiDoc.cpp. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocHeader constructs a decoder sized for kMobiHeaderLen without receiving the actual remaining buffer length. A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer. Opening the crafted document can crash SumatraPDF. This issue is fixed in version 3.6.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-26054 since 02/10/2026. The exploitation appears to be easy. The attack needs to be approached locally. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 3.6 eliminates this vulnerability.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• sumatrapdfreader

Name

• SumatraPDF

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5

Website

• Product: https://github.com/sumatrapdfreader/sumatrapdf/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion