OPNsense: XPath injection in MVC safe-delete

published 2026-10-15 25 d ago modified 2026-10-15 24 d ago also EUVD-2026-102116

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits: 0; none known

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.11, the safe-delete path reached through ApiMutableModelControllerBase::delBase() interpolates an unvalidated safe-delete token from the request URL into an XPath expression over config.xml before confirming that the token is a valid identifier. A user holding any one affected module privilege can send a crafted token to one of 21 affected delete endpoints covering Traffic Shaper, DHCP relay, Dnsmasq, Firewall Category, or Kea DHCP, causing the XPath to match configuration data across modules. The resulting error response exposes configuration item names, descriptions, reference paths, and UUIDs and provides an XPath substring-presence oracle, including for modules the user cannot otherwise access. The request does not modify configuration or perform a deletion. This issue is fixed in version 26.1.11.

Patch / fix

fixed in 1 links 2

opnsense opnsense 26.1.11

github.com/opnsense/core@631e147 commit
github.com/opnsense/core@d7054ce commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 24 d ago (2026-10-15)

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/opnsense/core/security/advisories/GHSA-98h6-479q-9q3w referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected products

opnsense core

Classification

Weakness

CWE-643 Improper Neutralization of Data within XPath Expressions

References

Sources

CVE List CVE-2026-58395
NVD CVE-2026-58395

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary