CVE-2026-71390 Overview
CVE-2026-71390 is an improper input validation vulnerability [CWE-20] affecting Adobe's CAI (Content Authenticity Initiative) Content Credentials. The flaw allows a local attacker to bypass security measures and gain unauthorized limited write access without user interaction. Adobe disclosed the issue in Security Bulletin APSB26-111.
The vulnerability carries a CVSS 3.1 score of 4.0 (Medium). Exploitation requires local access with low attack complexity and no privileges. The impact is limited to integrity, with no confidentiality or availability effects. No public proof-of-concept exists, and the flaw is not listed in the CISA Known Exploited Vulnerabilities catalog.
Critical Impact
An attacker with local access can bypass Content Credentials validation controls to achieve limited unauthorized write access, potentially undermining the integrity guarantees the SDK is designed to provide.
Affected Products
- Adobe CAI Content Credentials SDK
- Refer to Adobe Security Bulletin APSB26-111 for version-specific details
- Applications embedding vulnerable versions of the Content Authenticity SDK
Discovery Timeline
- 2026-08-11 - CVE-2026-71390 published to NVD
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-71390
Vulnerability Analysis
CVE-2026-71390 is categorized under [CWE-20] Improper Input Validation. The CAI Content Credentials SDK fails to properly validate specific input before processing, which allows an attacker to circumvent a security control enforced by the SDK. The result is a security feature bypass that grants limited write access outside the intended trust boundary.
Content Credentials are designed to bind provenance metadata to digital assets so that consumers can verify authorship and edit history. When input validation fails, an attacker can influence internal state or resources the feature is meant to protect, weakening these provenance guarantees.
The attack surface is local, which constrains the practical reach of the flaw. However, local vectors are relevant on shared workstations, in build systems handling untrusted content, and in developer environments processing assets from external contributors.
Root Cause
The root cause is missing or insufficient validation of untrusted input inside the Content Credentials handling logic. Without a strict validation layer, malformed or crafted values reach downstream operations that assume well-formed data, allowing the security check to be bypassed. Adobe has not published exploitation specifics beyond the advisory.
Attack Vector
A local attacker supplies crafted input to a component that consumes Content Credentials data. Because the vulnerability requires no privileges and no user interaction, an unprivileged local process can trigger the condition. Successful exploitation yields limited write access rather than full compromise, consistent with the low integrity impact rating. No public exploit code is available, and the EPSS score is 0.166% (6.272 percentile).
No verified proof-of-concept code is available. See the Adobe Security Bulletin APSB26-111 for vendor guidance.
Detection Methods for CVE-2026-71390
Indicators of Compromise
- Unexpected modifications to Content Credentials manifests or C2PA assertions on assets processed by affected SDK versions
- Local process activity invoking the Content Authenticity SDK with malformed or non-standard input payloads
- Integrity mismatches between signed provenance data and the underlying asset content
Detection Strategies
- Compare Content Credentials signatures and hashes against expected values in asset pipelines to identify tampered manifests
- Audit local process execution logs for non-standard invocations of applications that embed the CAI SDK
- Correlate file write events on provenance metadata stores with the identity of the invoking local user
Monitoring Recommendations
- Enable endpoint file integrity monitoring on directories that store Content Credentials output and SDK configuration
- Log SDK version telemetry across the fleet to identify hosts still running unpatched builds
- Alert on local process behavior that writes to provenance artifacts outside approved workflows
How to Mitigate CVE-2026-71390
Immediate Actions Required
- Inventory all applications and internal tooling that embed the CAI Content Credentials SDK
- Apply the fixed SDK version as documented in Adobe Security Bulletin APSB26-111
- Restrict local access on systems that process Content Credentials for untrusted assets
- Treat provenance data generated by unpatched versions as unverified until re-signed with a patched build
Patch Information
Adobe published fix guidance in Security Bulletin APSB26-111. Administrators should upgrade the CAI Content Credentials SDK to the version identified by Adobe in that bulletin. Consult Adobe Security Bulletin APSB26-111 for exact version numbers and download locations.
Workarounds
- Limit local logon rights on hosts that run Content Credentials processing until patches are applied
- Isolate asset ingestion pipelines that use the SDK from general-purpose workstations
- Validate Content Credentials output against a known-good pipeline before publishing assets externally
No verified configuration snippet is published by the vendor. Follow the remediation steps in Adobe Security Bulletin APSB26-111.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
