epiphany: TLS certificate warning bypass via race in tlsErrorPage message handler
Summary
| CVE | CVE-2026-115683 |
|---|---|
| State | PUBLISHED |
| Assigner | fedora |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-30 14:16:39 UTC |
| Updated | 2026-10-30 19:27:58 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 6.8 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS: 0.002200000 probability, percentile 0.126100000 (date 2026-11-02)
Problem Types: CWE-367 | CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-115683 | [email protected] | access.redhat.com | |
| gitlab.gnome.org/GNOME/epiphany/-/work_items/2978 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | gitlab.gnome.org | |
| beford.net/poc/ssl_poc.html | [email protected] | beford.net | |
| gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2245 | [email protected] | gitlab.gnome.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Fernando Munoz for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-10-21T00:00:00.000Z | Reported to Red Hat. |
| CNA | 2026-10-21T00:00:00.000Z | Made public. |
Workarounds
CNA: Until a fixed Epiphany build is installed, avoid following links from untrusted sites to HTTPS destinations, and do not rely on Epiphany for sensitive sites when browsing untrusted content. Restrict network access for untrusted browsing where practical (https://cmetaxonomy.org/entries/CME-203.html). Restarting the browser clears any attacker-installed certificate exceptions for the session.