Vulnerability · Published Dec 18, 2025 · Assigned by VulnCheck
CVE-2025-34451rofl0r/proxychains-ng <= 4.17 Stack-based Buffer Overflow
Medium 6.9
In plain English
A medium-severity stack buffer overflow in proxychains-ng from rofl0r. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | proxychains-ng | no fix listed | DEBIAN-CVE-2025-34451 |
| Debian:13 | proxychains-ng | no fix listed | DEBIAN-CVE-2025-34451 |
| Debian:14 | proxychains-ng | 4.17-3.1 | DEBIAN-CVE-2025-34451 |
| Ubuntu:22.04:LTS | proxychains-ng | no fix listed | UBUNTU-CVE-2025-34451 |
| Ubuntu:24.04:LTS | proxychains-ng | no fix listed | UBUNTU-CVE-2025-34451 |
| Ubuntu:25.10 | proxychains-ng | no fix listed | UBUNTU-CVE-2025-34451 |
| Ubuntu:26.04:LTS | proxychains-ng | no fix listed | UBUNTU-CVE-2025-34451 |
| Ubuntu:26.10 | proxychains-ng | no fix listed | UBUNTU-CVE-2025-34451 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| rofl0r | proxychains-ng | 0 – through 4.17 |
Weakness: CWE-121 · 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
- https://github.com/marlinkcyber/advisories/blob/main/advisories/MCSAID-2025-008-proxychains-ng-stack-buffer-overflow-proxy_from_string.md technical-description, exploit
- https://github.com/rofl0r/proxychains-ng/issues/606 issue-tracking
- https://github.com/httpsgithu/proxychains-ng/commit/cc005b7 patch
- https://www.vulncheck.com/advisories/rofl0r-proxychains-ng-stack-based-buffer-overflow third-party-advisory