CVE-2026-55586

Published: Ago 20, 2026 Last Modified: Ago 20, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 6,6
Source: [email protected]
Attack Vector: local
Attack Complexity: low
Privileges Required: none
User Interaction: required
Scope: unchanged
Confidentiality: low
Integrity: high
Availability: low

Description

AI Translation Available

SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, a crafted CHM file can supply malformed LZX Huffman code lengths to make_decode_table in ext/CHMLib/lzx.c. In the long-code branch, the function writes new internal nodes through next_symbol before validating that the canonical Huffman table has overflowed. The PRETREE case can write beyond the 104-entry PRETREE_table into adjacent heap state in struct LZXstate when reached through chm_open, chm_retrieve_object, LZXdecompress, and BUILD_TABLE. This produces heap memory corruption in the parser process, while arbitrary code execution has not been demonstrated. No fixed version is available as of this review.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0013
Percentile
0,0th
Updated

Single Data Point

Only one EPSS measurement is available for this CVE. Trend analysis requires multiple data points over time.

119

Improper Restriction of Operations within the Bounds of a Memory Buffer

Stable
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Confidentiality Availability
Potential Impacts:
Execute Unauthorized Code Or Commands Modify Memory Read Memory Dos: Crash, Exit, Or Restart Dos: Resource Consumption (Cpu) Dos: Resource Consumption (Memory)
Applicable Platforms
Languages: Memory-Unsafe, C, C++, Assembly
Likelihood of Exploit: High
View CWE Details
787

Out-of-bounds Write

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Availability Other
Potential Impacts:
Modify Memory Execute Unauthorized Code Or Commands Dos: Crash, Exit, Or Restart Unexpected State
Applicable Platforms
Languages: Memory-Unsafe, C, C++, Assembly
Technologies: ICS/OT
Likelihood of Exploit: High
View CWE Details
https://github.com/sumatrapdfreader/sumatrapdf/commit/13b3d…
https://github.com/sumatrapdfreader/sumatrapdf/commit/13b3d4204dd12d93d426f2157…
https://github.com/sumatrapdfreader/sumatrapdf/security/adv…
https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-m423-rp…