---
title: "CVE-2026-112021: snac2 - Buffer Overflow"
description: "snac2 < 2.93 contains a heap-based buffer overflow caused by improper handling of \\u0000 escape sequences in _xs_json_load_lexer(), letting unauthenticated remote attackers corrupt heap memory and crash the server via crafted JSON strings."
url: https://panop.io/threat-heartbeat/CVE-2026-112021/
---

# CVE-2026-112021 snac2 - Buffer Overflow

snac2 < 2.93 contains a heap-based buffer overflow caused by improper handling of \\u0000 escape sequences in \_xs\_json\_load\_lexer(), letting unauthenticated remote attackers corrupt heap memory and crash the server via crafted JSON strings.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-112021)

## Details

Type

Buffer Overflow

Impact

Denial of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

18 October 2026

Updated

19 October 2026

Weakness

[CWE-122](https://cwe.mitre.org/data/definitions/122.html)

## Vendor fix

Update to version 2.93 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-112021](https://nvd.nist.gov/vuln/detail/CVE-2026-112021)
- [https://nullenvk.pl/posts/02-snac2-json](https://nullenvk.pl/posts/02-snac2-json)
- [https://www.vulncheck.com/advisories/snac2-before-2.93-heap-based-buffer-overflow-via-json-parser-xs-json-load-lexer](https://www.vulncheck.com/advisories/snac2-before-2.93-heap-based-buffer-overflow-via-json-parser-xs-json-load-lexer)
- [https://codeberg.org/grunfink/snac2](https://codeberg.org/grunfink/snac2)
- [https://codeberg.org/grunfink/snac2/commit/ec2c5c2046e0381bc942ec5d0d05ec861fe377e7](https://codeberg.org/grunfink/snac2/commit/ec2c5c2046e0381bc942ec5d0d05ec861fe377e7)
- [https://codeberg.org/grunfink/snac2/releases/tag/2.93](https://codeberg.org/grunfink/snac2/releases/tag/2.93)
- [https://codeberg.org/grunfink/snac2/src/tag/2.92/xs\_json.h#L283-L285](https://codeberg.org/grunfink/snac2/src/tag/2.92/xs_json.h#L283-L285)
- [https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b](https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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