CVE-2026-55246
Received Received - Intake

Heap Corruption in bincookie Binarycookies Parser

Vulnerability report for CVE-2026-55246, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-10-15

Last updated on: 2026-10-15

Assigner: GitHub, Inc.

Description

bincookie is a header-only binarycookies parser. Prior to 0.1.9, bincookie_init_file() in bincookie.h allocates a buffer using the actual .binarycookies file length but trusts the file-controlled num_pages field as the loop bound for byte-swapping page_sizes entries. A crafted file can make the loop read and write beyond the heap allocation, and related unvalidated page sizes and cookie_offsets can drive additional out-of-bounds accesses in page and cookie iteration. Applications that parse an attacker-supplied binarycookies file may crash or suffer heap corruption that can potentially enable code execution. This issue is fixed in version 0.1.9.

CVSS Scores

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Meta Information

Published
2026-10-15
Last Modified
2026-10-15
Generated
2026-10-16
AI Q&A
2026-10-15
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Tatsh bincookie < 0.1.9

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
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().
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

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Executive Summary

CVE-2026-55246 is a heap buffer overflow in the bincookie library's bincookie_init_file() function. It occurs because the function allocates a buffer based on the .binarycookies file length but trusts the file-controlled num_pages field for loop bounds. A crafted file can make the loop read and write beyond the heap allocation, leading to out-of-bounds memory access. This can cause heap corruption, crashes, or potentially enable code execution.

Detection Guidance

To detect this vulnerability, check the version of the bincookie library in use. If it is version 0.1.8 or lower, the system is vulnerable. Commands like 'find / -name bincookie.h 2>/dev/null' or 'ldconfig -p | grep bincookie' may help locate the library.

Impact Analysis

If you use an application that parses attacker-supplied .binarycookies files with a vulnerable version of bincookie (<= 0.1.8), your system may crash or suffer heap corruption. This could allow an attacker to execute arbitrary code, escalate privileges, or steal sensitive data. The attack requires local access but no privileges or user interaction.

Mitigation Strategies

Immediately upgrade the bincookie library to version 0.1.9 or later. Remove or restrict access to applications parsing untrusted .binarycookies files until the update is applied. Monitor for crashes or heap corruption in applications using bincookie.

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