Vulnerability · Published Oct 15, 2026 · Assigned by GitHub_M

CVE-2026-57155OPNsense: Root RCE via Arbitrary File Write in GeoIP Alias Importer

Critical 9.9

In plain English

A critical-severity path traversal in core from opnsense. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 59% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 3.1)9.9Critical

Exploit odds (30 days)0.9%top 41.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack tooling1Public PoC

Official description

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the Firewall Alias GeoIP importer's process_zip() and process_gzip() paths in src/opnsense/scripts/filter/lib/alias/geoip.py use an unvalidated CSV country_code value to construct output filenames below /usr/local/share/GeoIP/alias. A user with Firewall Alias Edit privilege can configure an attacker-controlled GeoIP source URL and supply an archive whose country code traverses into another existing directory, causing attacker-controlled content to be written as root with an -IPv4 or -IPv6 suffix. A crafted newsyslog fragment and oversized log file can use the default hourly root cron job to execute commands as root, resulting in complete firewall compromise. This issue is fixed in version 26.1.11.

Affected products (as reported)

Vendor	Product	Versions
opnsense	core	< 26.1.11

Weakness: CWE-22, CWE-73, CWE-78 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

https://github.com/opnsense/core/security/advisories/GHSA-wjqq-rfmm-v5h3 x_refsource_CONFIRM
https://github.com/opnsense/core/commit/c46aced9c47d956167e294911113bc334fea5f48 x_refsource_MISC
https://github.com/opnsense/core/commit/e7fbfaa7f5e070da667e3f243da11fd3d4b731fa x_refsource_MISC
https://hackerask.com/posts/opnsense x_refsource_MISC