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.
CVE-2026-108164
MEDIUMPre-NVD 6.56.5
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 6.5Exploit: None knownExposed services: Not assessed
An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.
- CVSS v3
- 6.5
- EG Score
- 6.5MEDIUMlow confidence
- EG Risk
- 34EG Risk 34/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).Action: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).
An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 10, 2026
Last Modified
October 10, 2026
Advisory Details (6)
Auto-updated Oct 10, 2026Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic
Open Source Social Network (OSSN) through 10.1 IDOR via Message Attachment Route | Advisories | VulnCheck
https://www.vulncheck.com/advisories/open-source-social-network-ossn-through-10.1-idor-via-message-attachment-routegeneric
GitHub - opensource-socialnetwork/opensource-socialnetwork: Open Source Social Network (OSSN) is a powerful open-source social networking software developed in PHP. It enables you to create a fully functional social networking website that fosters community engagement and helps your members form meaningful social relationships. · GitHub
https://github.com/opensource-socialnetwork/opensource-socialnetworkgeneric
opensource-socialnetwork/components/OssnMessages/ossn_com.php at 48b53f5b95488187715b2d5b5ae46a993267f83d · opensource-socialnetwork/opensource-socialnetwork · GitHub
https://github.com/opensource-socialnetwork/opensource-socialnetwork/blob/48b53f5b95488187715b2d5b5ae46a993267f83d/components/OssnMessages/ossn_com.php#L149-L156generic
OSSN IDOR - Unauthorized Access to Message Attachments - HackMD
https://hackmd.io/@leediay/ossn-idor-message-attachmentgithub_commit
commit 2e9733d8eaaf (opensource-socialnetwork/opensource-socialnetwork)
Fix landed in opensource-socialnetwork/opensource-socialnetwork commit 2e9733d8eaaf — awaiting tagged release
https://github.com/opensource-socialnetwork/opensource-socialnetwork/commit/2e9733d8eaafccdaef3d9b498348c8332e51f48bgeneric
[B] Check file download in messages ownership checking · Issue #2641 · opensource-socialnetwork/opensource-socialnetwork · GitHub
https://github.com/opensource-socialnetwork/opensource-socialnetwork/issues/2641Vendor Advisories for CVE-2026-108164(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-10-10 14:25 UTCEG score recompute
- 2026-10-10 14:00 UTCEG score recompute
- 2026-10-10 14:00 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-108164?
CVE-2026-108164 is a medium vulnerability published on October 10, 2026. 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…
When was CVE-2026-108164 disclosed?
CVE-2026-108164 was first published on October 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-108164?
CVE-2026-108164 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-108164?
An upstream fix for CVE-2026-108164 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-108164 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-108164
Is Your Infrastructure Affected by CVE-2026-108164?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.