VulnerabilityDeferred

CVE-2026-47725

SameSite=Lax on the session cookie prevents most cross-site form submits but does not protect: top-level form-submit navigations from third-party pages (some browsers still send Lax cookies on top-level POSTs); same-registrable-domain attackers…

MEDIUM 6.9EPSS 0.15%

Does this matter?

Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own.

Description

nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.3, every /ui/* POST / PUT / PATCH / DELETE route processes the request as soon as the session cookie validates. SameSite=Lax on the session cookie prevents most cross-site form submits but does not protect: top-level form-submit navigations from third-party pages (some browsers still send Lax cookies on top-level POSTs); same-registrable-domain attackers (sibling-subdomain XSS, subdomain takeover); the GET /ui/logout route, which a third-party <img src=".../ui/logout"> can force-trigger. This issue has been patched in version 0.3.3.

CVSS 4.0: 6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.15% probability · 5th percentile
CISA KEV: Not listed
Weakness: CWE-352
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.