---
id: "CVE-2026-112273"
kind: "vulnerability"
aliases: ["CVE-2026-112273"]
title: "libtins: crafted DNS packet causes one-byte heap out-of-bounds read"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["c++", "libtins", "network-tools", "package", "packet-parsing"]
not_affected_if: ["no-libtins-dependency", "trusted-traffic-only"]
published_at: "2026-10-19T14:17:05+00:00"
first_seen_at: "2026-10-23T21:57:18+00:00"
updated_at: "2026-10-25T03:40:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112273", "first_seen_at": "2026-10-23T21:57:18+00:00"}]
---

# libtins: crafted DNS packet causes one-byte heap out-of-bounds read

libtins is a C++ packet-sniffing and crafting library, and its DNS name parser reads one byte past the end of the packet buffer when a label ends exactly at the packet end. A remote attacker who sends a crafted DNS packet can crash applications that parse it, especially on hardened allocators.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check whether the project depends on libtins, for example with `grep -ri libtins` in the build files or `ldd` on binaries that link it.
- Confirm the installed version, and treat anything at or below `4.6` as affected.

## Timeline

- 2026-10-23T21:57:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112273

## From the sources

libtins through 4.6 contains a heap out-of-bounds read vulnerability in DNS::compose_name in src/dns.cpp that allows remote attackers to read past the packet buffer by sending a label ending exactly at the packet end. Attackers can deliver crafted DNS packets whose additional, answer, or authority records trigger a one-byte read when parsed, crashing applications on hardened allocators.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_