What is the CVSS score of CVE-2026-50739?

CVE-2026-50739 has a CVSS 3.0 base score of 4.3 (Medium). CVSS vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N. EPSS exploitation probability: 0.2%.

Revive Adserver CVE-2026-50739

EUVD-2026-39601 MEDIUM

Improper Access Control (CWE-284)

2026-06-26 hackerone

GHSA-v78r-pfp2-f4c7

PHP Authentication Bypass Adserver Revive

4.3

CVSS 3.0 · Vendor: hackerone

Severity by source

Vendor (hackerone) PRIMARY

4.3 MEDIUM

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

vuln.today AI

4.3 MEDIUM

Low-privilege authentication required over network; impact is integrity-only, limited to cross-manager ownership record pollution with no confidentiality or availability effect.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

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

Primary rating from Vendor (hackerone).

CVSS VectorVendor: hackerone

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Jun 26, 2026 - 01:45 vuln.today

DescriptionCVE.org

A bypass for CVE‑2026‑34913 exists with proper ownership validation that had not been applied to the reverse operation of linking campaigns and trackers through the tracker-campaigns.php script in Revive Adserver 6.0.7 and earlier. As a result, a low‑privileged user could link their trackers to campaigns owned by other managers on the same instance, leading to inconsistent ownership relationships.

AnalysisAI

Ownership validation bypass in Revive Adserver 6.0.7 and earlier allows a low-privileged authenticated user to link their own trackers to campaigns belonging to other managers on the same instance via the tracker-campaigns.php script. This is a bypass of the fix introduced for CVE-2026-34913, which applied ownership checks only to the forward linking operation but omitted the reverse direction. The impact is confined to integrity - specifically, creation of inconsistent cross-manager ownership relationships - with no confidentiality or availability consequences. No public exploit identified at time of analysis.

Technical ContextAI

Revive Adserver is an open-source PHP-based ad serving platform (cpe:2.3:a:revive:adserver:*:*:*:*:*:*:*:*). The tracker-campaigns.php script manages the bidirectional relationship between tracker and campaign entities. The prior fix for CVE-2026-34913 introduced ownership validation for one direction of this linking operation but failed to apply the same guard to the reverse operation, a classic incomplete-fix pattern. CWE-284 (Improper Access Control) captures the root cause: the authorization decision - verifying campaign ownership before permitting a link - was not uniformly enforced across all code paths executing the same logical action. The PHP tag confirms the server-side language context and that no client-side exploitation is involved.

RemediationAI

Upgrade Revive Adserver to a version that incorporates the corrected ownership validation for the reverse tracker-campaign linking operation in tracker-campaigns.php. No exact patched release version is confirmed from the available reference data; the HackerOne report at https://hackerone.com/reports/3780709 should be consulted for the vendor's official fix version once the report becomes public. As a compensating control for multi-manager deployments pending a patch, administrators can restrict low-privileged users' access to the tracker-campaigns.php endpoint via web server ACLs or application-level role restrictions, accepting the trade-off that tracker-campaign linking functionality will be unavailable to those users. Single-manager deployments face negligible risk and no immediate action is required beyond monitoring for an official patch.