CVE-2026-43877

CVE-2026-43877 is a medium-severity vulnerability with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-352.

Key facts

Description

WWBN AVideo is an open source video platform. In versions up to and including 29.0, objects/userSavePhoto.php is a legacy profile-photo endpoint that accepts a base64 POST parameter and writes the decoded bytes to videos/userPhoto/photo<users_id>.png. Its only access control is User::isLogged(). It does not end in .json.php, so it is excluded from the project's global autoCSRFGuard (which is suffix-scoped in objects/include_config.php). There is no CSRF token, no Origin/Referer check, and no MIME validation of the decoded bytes. Because AVideo's default cookie policy is SameSite=None; Secure on HTTPS (objects/functionsPHP.php:227), an attacker who lures a logged-in user to a malicious page can overwrite that user's profile photo with arbitrary bytes and also triggers a site-wide clearCache(true) on every forged request. Commit 9c38468041505e637101c5943c5370c68f48e3ac contains an updated fix.

Frequently asked questions

What is CVE-2026-43877?
WWBN AVideo is an open source video platform. In versions up to and including 29.0, objects/userSavePhoto.php is a legacy profile-photo endpoint that accepts a base64 POST parameter and writes the decoded bytes to videos/userPhoto/photo<users_id>.png. Its only access control is User::isLogged(). It does not end in .json.php, so it is excluded from the project's global autoCSRFGuard (which is suffix-scoped in objects/include_config.php). There is no CSRF token, no Origin/Referer check, and no MIME validation of the decoded bytes. Because AVideo's default cookie policy is SameSite=None; Secure on HTTPS (objects/functionsPHP.php:227), an attacker who lures a logged-in user to a malicious page can overwrite that user's profile photo with arbitrary bytes and also triggers a site-wide clearCache(true) on every forged request. Commit 9c38468041505e637101c5943c5370c68f48e3ac contains an updated fix.
How severe is CVE-2026-43877?
CVE-2026-43877 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2026-43877 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-43877?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-43877 have an EU (EUVD) identifier?
Yes. CVE-2026-43877 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29313.
When was CVE-2026-43877 published?
CVE-2026-43877 was published on 2026-05-11 and last updated on 2026-06-17.

References

Other CWE-352 (Cross-Site Request Forgery (CSRF)) vulnerabilities

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