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Public proof of conceptFix availableAwaiting NVD analysis

CVE-2026-115683

epiphany: TLS certificate warning bypass via race in tlsErrorPage message handler

A public proof of concept exists; no exploitation attested.

  • Published2026-10-30
  • WeaknessCWE-367

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-10-3013:33CVE publishedCNA

Versions per branch

Products declared by the CNA1 product

As fedora, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-02

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • epiphanyopenSUSE:Tumbleweedall versions · fixed in 51.2-1.1
  • epiphany-browserUbuntu:26.10all versions · no fixed version listed
  • epiphany-browserUbuntu:26.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:24.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:22.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:20.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:18.04:LTSall versions · no fixed version listed
  • epiphany-browserUbuntu:16.04:LTSall versions · no fixed version listed

3 more package ranges on OSV.dev

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Published
2026-10-30
Last Modified
2026-11-02
NVD status
Awaiting Analysis
GitHub Advisory
GHSA-rgq4-6fxx-v9rg

Frequently asked questions

What is CVE-2026-115683?

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.

Is CVE-2026-115683 actively exploited?

A proof-of-concept exploit exists for CVE-2026-115683, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-115683?

CVE-2026-115683 has a CVSS v3 base score of 6.8 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.

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