CVE-2026-108164
Open Source Social Network (OSSN) through 10.1 contains an insecure direct object reference vulnerability in components/OssnMessages/ossn_com.php that allows authenticated users to read other users' private message attachments.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Open Source Social Network (OSSN) through 10.1 contains an insecure direct object reference vulnerability in components/OssnMessages/ossn_com.php that allows authenticated users to read other users' private message attachments. Attackers can request the /messages/attachment/{guid} route with sequential or guessed file GUIDs to retrieve attachments from private conversations without sender or recipient verification.
- CVSS 4.0
- 7.1 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/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
- 0.26% probability · 17th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-639
- Source
- disclosure@vulncheck.com
EPSS moved from 0.3% on 11 October 2026 to 0.3% on 26 October 2026.
References
- https://github.com/opensource-socialnetwork/opensource-socialnetwork
- https://github.com/opensource-socialnetwork/opensource-socialnetwork/blob/48b53f5b95488187715b2d5b5ae46a993267f83d/components/OssnMessages/ossn_com.php#L149-L156
- https://github.com/opensource-socialnetwork/opensource-socialnetwork/commit/2e9733d8eaafccdaef3d9b498348c8332e51f48b
- https://github.com/opensource-socialnetwork/opensource-socialnetwork/issues/2641
- https://hackmd.io/@leediay/ossn-idor-message-attachment
- https://www.vulncheck.com/advisories/open-source-social-network-ossn-through-10.1-idor-via-message-attachment-route
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.