CERT-FR flags Opera Neon security bypass flaw
A vulnerability in Opera Neon allows attackers to bypass security policy via improper verification of a communication channel source.
Sourcecert.cyber.gouv.fr — open the original
What to check
- Applies to
- The 1 CVE named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- No exploitation in the wild and no public exploit is recorded for the CVEs named.
CERT-FR issued an advisory regarding a vulnerability in Opera Neon, the AI-enhanced browser from Opera. The flaw stems from improper verification of the source of a communication channel, which could allow an attacker to bypass the browser's security policy. This is tracked as CVE-2026-123139 and was disclosed via Opera's own security advisory on 12 November 2026.
Affected systems are instances of Opera Neon that have not applied the latest security patch. CERT-FR does not indicate evidence of active exploitation in the wild; the advisory is a standard vulnerability notification. Defenders should refer to Opera's official security bulletin for patch details and ensure all Opera Neon installations are updated to the fixed version to mitigate the security policy bypass risk.
Mentioned in this report
Source reporting: https://www.cert.cyber.gouv.fr/avis/CERTFR-2026-AVI-1532
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