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Fencer Intel
high 7.8

CVE-2026-55246 json

bincookie: Heap buffer overflow via unvalidated `num_pages` when parsing a `.binarycookies` file

published 4mo ago modified 26d ago also EUVD-2026-102203 , GHSA-22pc-xxw4-q849

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository Tatsh/bincookie. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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.

Patch / fix

Is CVE-2026-55246 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55246 updated cvss 7.8

bincookie: bincookie: Arbitrary code execution via crafted binary cookies file

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
27d ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/Tatsh/bincookie/security/advisories/GHSA-22pc-xxw4-q849 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Tatsh bincookie

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of Tatsh/bincookie published their own advisory on GitHub. Reviewed sources take precedence over it.