# CVE-2026-8295: Integer overflow in simdjson

> An integer overflow in simdjson's document-builder API on 32-bit platforms can lead to out-of-bounds reads, potentially causing information disclosure or memory corruption.

- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 May 2026
- **Updated:** 14 May 2026
- **Also known as:** GHSA-fh2w-3fv3-7vw2

## What is CVE-2026-8295?

CVE-2026-8295 is a medium-severity vulnerability in simdjson, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-8295?


## How do I fix CVE-2026-8295?

No fix has been published for CVE-2026-8295 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-8295 being exploited?

There is no known exploitation of CVE-2026-8295 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8295 and fix it if it is affected.

What it is: CVE-2026-8295 is a medium-severity vulnerability in simdjson, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-8295 in the wild and no public exploit code.

Affected product: simdjson. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-8295/ (Markdown: https://insights.sbomify.com/CVE-2026-8295/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8295
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8295
- OSV: https://osv.dev/vulnerability/CVE-2026-8295

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8295/
Summaries are generated and may contain mistakes; the official description above is the record.