---
title: "CVE-2025-34451\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2025-34451?format=md
keywords: index, follow
---

# CVE-2025-34451

Publication date 18 December 2025

Last updated 10 July 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.8 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2025-34451?format=md#impact-score)

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## Description

rofl0r/proxychains-ng versions up to and including 4.17 and prior to commit
cc005b7 contain a stack-based buffer overflow vulnerability in the function
proxy\_from\_string() located in src/libproxychains.c. When parsing crafted
proxy configuration entries containing overly long username or password
fields, the application may write beyond the bounds of fixed-size stack
buffers, leading to memory corruption or crashes. This vulnerability may
allow denial of service and, under certain conditions, could be leveraged
for further exploitation depending on the execution environment and applied
mitigations.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| proxychains-ng | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 25.04 plucky | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:

CVSS v4.0

[CVSS v4.0](https://ubuntu.com/security/CVE-2025-34451?format=md)
[CVSS v3.0](https://ubuntu.com/security/CVE-2025-34451?format=md)

**Base score**

6.9 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Local |
  | Attack complexity | Low |
  | Attack requirements | None |
  | Privileges required | None |
  | User interaction | None |
  | Vulnerable system - Confidentiality impact | None |
  | Vulnerable system - Integrity impact | None |
  | Vulnerable system - Availability impact | High |
  | Subsequent system - Confidentiality impact | None |
  | Subsequent system - Integrity impact | None |
  | Subsequent system - Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.9 · Medium |
  | Base + Threat score | - |
  | Base + Environmental score | - |
  | Base + Threat + Environmental score | - |

**Vector:** CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-34451)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2025-34451)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2025-34451)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2025-34451)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2025-34451>
* <https://github.com/httpsgithu/proxychains-ng/commit/cc005b7>
* <https://github.com/marlinkcyber/advisories/blob/main/advisories/MCSAID-2025-008-proxychains-ng-stack-buffer-overflow-proxy_from_string.md>
* <https://github.com/rofl0r/proxychains-ng/issues/606>
* <https://www.vulncheck.com/advisories/rofl0r-proxychains-ng-stack-based-buffer-overflow>