What’s Vulnerable › Vulnerabilities

CVE-2026-8295: Integer overflow in simdjson

• Severity: medium (CVSS 6.9 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-14 · updated 2026-06-17
• Weakness: CWE-190

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

Affected products

• simdjson: before 4.6.4 — fixed in 4.6.4

How to fix

Upgrade to a fixed version: simdjson 4.6.4. Check the vendor advisory for mitigations.

References

• https://cert.pl/posts/2026/05/CVE-2026-8295
• https://github.com/simdjson/simdjson/releases/tag/v4.6.4

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