OpenSave before 2.4.0-beta.1 Authentication Bypass via Spoofed Relay Sender

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

OpenSave before 2.4.0-beta.1 fails to validate sender identity in WAN relay requests, allowing unpaired room members to impersonate paired devices by spoofing the RelayMessage From field. Attackers who know the room code can join, read paired peer identifiers from announcements, and send forged requests to access protected sync routes including save data, snapshots, and file operations.

Source published

30 Sep 2026 14:48:57 UTC

Source modified

2 Oct 2026 16:19:36 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

CVSS 3.1 · 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L