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

Overview

State: PUBLISHED
Assigner (CNA): CERT-PL
CVSS severity: MEDIUM
CVSS score: 6.9 / 10
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Effective score: 6.9 / 10 MEDIUM source: CNA overview
CWE(s): CWE-190
Reserved: 2026-05-11
Published: 2026-05-14 12:27 UTC
Last updated: 2026-05-14 19:48 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/8xxx/CVE-2026-8295.json
Linked Threat: CVE-2026-8295 — CVE-2026-8295

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-14 11:16:18 UTC
NVD last modified: 2026-05-19 15:17:37 UTC
EPSS score: 0.0006 (probability of exploitation in next 30 days)
EPSS percentile: 17.35% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-30265
Assigner: CERT-PL
Published: May 14, 2026, 10:27:41 AM
Updated: May 14, 2026, 5:48:38 PM
EUVD base score (CVSS 4.0): 6.9 / 10
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
EUVD-reported EPSS: 0.0600
Vendors: simdjson
Products: simdjson (0 <4.6.4)
Aliases: GHSA-fh2w-3fv3-7vw2

ENISA 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

EUVD references (2)

Microsoft Security Response Center MSRC

Microsoft's vendor-authoritative record from the Security Update Guide — its own CVSS score, impact, severity rating, exploit assessment, and KB-article fixes. Refreshed 2026-08-12 01:09 UTC (source: CVRF).

MS severity: Low
Release: 2026-May

Affected products (1)

Vendor	Product	Versions	Platforms
simdjson	simdjson	`0` (affected)	32 bit

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

https://github.com/simdjson/simdjson/releases/tag/v4.6.4 release-notes
https://cert.pl/posts/2026/05/CVE-2026-8295 third-party-advisory

MITRE references (2) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

https://cert.pl/posts/2026/05/CVE-2026-8295 third-party-advisory
https://github.com/simdjson/simdjson/releases/tag/v4.6.4 release-notes

Web references (4)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

MSRC update guide: CVE-2026-8295 msrc
https://nvd.nist.gov/vuln/detail/CVE-2026-8295 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-8295 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org

NVD-tagged references (2)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

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

Remediations (14)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review

web:blog.qualys.com

Microsoft's February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here's a quick…

2026-05-23 20:53 UTC
CISA Warns of Exploited Microsoft Defender 0-Day Flaws

web:cyberpress.org

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

2026-05-23 20:53 UTC
Microsoft Releases Mitigation for Windows BitLocker Security Bypass 0 ...

web:cybersecuritynews.com

No patch has been released yet; Microsoft has instead issued a multi-step manual mitigation guide while a formal security update is prepared. Windows BitLocker Security Bypass The vulnerability originates in WinRE's handling of the BootExecute registry value under HKLM\ControlSet001\Control\Session Manager.

2026-05-23 20:53 UTC
Nvd - Cve-2026-8957

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-23 20:53 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-23 20:53 UTC
February's Patch Tuesday release fixes 59 flaws ... - Computerworld

web:www.computerworld.com

Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...

2026-05-23 20:53 UTC
Microsoft Patch Tuesday - February 2026 - Lansweeper

web:www.lansweeper.com

Which vulnerabilities, issues, and other things did Microsoft update? Discover what's new using Lansweeper's Patch Tuesday February 2026 summary.

2026-05-23 20:53 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-05-23 20:53 UTC
Microsoft Rolls Out Mitigations for 'YellowKey' BitLocker ...

web:www.securityweek.com

Microsoft has announced mitigations for CVE - 2026 -45585, a BitLocker bypass triggered via FsTx in Windows Recovery.

2026-05-23 20:53 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-23 20:53 UTC
Windows Kerberos RC4 deprecation: what will break in Active ... - 4sysops

web:4sysops.com

Starting in April 2026 , Windows updates will change the default Kerberos ticket issuance behavior to AES-SHA1 for accounts without explicit encryption settings, while RC4 can still be used where explicitly enabled. This change, driven by CVE - 2026 -20833, affects every Windows Server environment where service accounts or devices still rely on RC4. Any service account, NAS device, or legacy ...

2026-05-26 02:55 UTC
CVE-2026-8295 - GitHub Advisory Database

web:github.com

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 ...

2026-05-26 02:55 UTC
Nvd - Cve-2026-45585

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-26 02:55 UTC
Windows 11 April 2026 Update tested: What's new, improved and fixed

web:www.windowslatest.com

Windows 11 April 2026 update adds Narrator Copilot support, faster Settings, File Explorer fixes, and key security improvements.

2026-05-26 02:55 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-8295.json.

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