Description
A race condition in Epiphany allows a malicious website to bypass the TLS/SSL certificate warning page.
Epiphany registers the main-world script message handler "tlsErrorPage" so its internal TLS error page can implement "Accept Risk and Proceed". The handler was registered immediately before loading the error page, leaving a brief window where the previously loaded untrusted origin could still call window.webkit.messageHandlers.tlsErrorPage.postMessage(...). The only authorization check compares a numeric WebKit page id that increments predictably; an attacker can burst-guess ids and approve a certificate exception with no user click.
If a victim visits malicious site A that redirects to site B with an invalid certificate, site A can, for a few milliseconds, disable TLS certificate error warnings for host B until Epiphany is restarted, enabling man-in-the-middle or site spoofing for that host.
Upstream report: https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2978
Proof of concept: https://beford.net/poc/ssl_poc.html
Fix: https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2245 (register handlers on LOAD_COMMITTED). No fixed release tagged yet; reporter and maintainer describe all current versions as affected. Maintainer notes the risky registration timing dates to commit 1da1caed (Epiphany 45.x era); before that the handlers were always registered and similarly reachable from web content.
Published: n/a
Score: 6.8 Medium
EPSS: n/a
KEV: No
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History

Sat, 24 Oct 2026 01:45:00 +0000

Type Values Removed Values Added
First Time appeared Gnome
Gnome epiphany
Vendors & Products Gnome
Gnome epiphany

Sat, 24 Oct 2026 00:30:00 +0000

Type Values Removed Values Added
Description A race condition in Epiphany allows a malicious website to bypass the TLS/SSL certificate warning page. Epiphany registers the main-world script message handler "tlsErrorPage" so its internal TLS error page can implement "Accept Risk and Proceed". The handler was registered immediately before loading the error page, leaving a brief window where the previously loaded untrusted origin could still call window.webkit.messageHandlers.tlsErrorPage.postMessage(...). The only authorization check compares a numeric WebKit page id that increments predictably; an attacker can burst-guess ids and approve a certificate exception with no user click. If a victim visits malicious site A that redirects to site B with an invalid certificate, site A can, for a few milliseconds, disable TLS certificate error warnings for host B until Epiphany is restarted, enabling man-in-the-middle or site spoofing for that host. Upstream report: https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2978 Proof of concept: https://beford.net/poc/ssl_poc.html Fix: https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2245 (register handlers on LOAD_COMMITTED). No fixed release tagged yet; reporter and maintainer describe all current versions as affected. Maintainer notes the risky registration timing dates to commit 1da1caed (Epiphany 45.x era); before that the handlers were always registered and similarly reachable from web content.
Title epiphany: epiphany: TLS certificate warning bypass via race in tlsErrorPage message handler
Weaknesses CWE-367
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'}

threat_severity

Moderate


cve-icon MITRE

No data.

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-21T00:00:00Z

Links: CVE-2026-115683 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-24T01:30:18Z

Weaknesses
  • CWE-367

    Time-of-check Time-of-use (TOCTOU) Race Condition