CVE-2025-34451: Proxychains-ng buffer overflow (CVSS 7.8)

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.

CVSS 3.1 breakdown

Attack vectorLocal

Attack complexityLow

Privileges requiredNone

User interactionRequired

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Affected products

Proxychains-ng≤ 4.17

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

Patch & vendor advisories

References

https://github.com/httpsgithu/proxychains-ng/commit/cc005b7Patch
https://github.com/marlinkcyber/advisories/blob/main/advisories/MCSAID-2025-008-proxychains-ng-stack-buffer-overflow-proxy_from_string.mdExploitThird Party Advisory
https://github.com/rofl0r/proxychains-ng/issues/606ExploitPatch
https://www.vulncheck.com/advisories/rofl0r-proxychains-ng-stack-based-buffer-overflowThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2025-34451 being actively exploited?

CVE-2025-34451 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.27%.

How severe is CVE-2025-34451?

CVE-2025-34451 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 0.27% probability of exploitation.

Which products are affected by CVE-2025-34451?

Affected products include Proxychains-ng.

How do I fix CVE-2025-34451?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-34451 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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