CVE-2026-8295

Description

An integer overflow vulnerability in the simdjson document-builder API allows incorrect buffer size calculations in "string_builder::escape_and_append()" when processing very large input strings on platforms with limited "size_t" width (e.g., 32-bit builds). The overflow can cause insufficient buffer allocation, leading to out-of-bounds memory reads in SIMD routines and potentially resulting in information disclosure, memory corruption, or malformed JSON output. This vulnerability has been fixed in 4.6.4 release

PUBLISHED Reserved 2026-05-11 | Published 2026-05-14 | Updated 2026-05-14 | Assigner CERT-PL

Problem types

CWE-190 Integer Overflow or Wraparound

Product status

Credits

Michał Majchrowicz (AFINE) finder

Marcin Wyczechowski (AFINE) finder

References

github.com/simdjson/simdjson/releases/tag/v4.6.4 release-notes

cert.pl/posts/2026/05/CVE-2026-8295 third-party-advisory

cve.org (CVE-2026-8295)

nvd.nist.gov (CVE-2026-8295)

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