sanitize iframe bodyClasses and bodyStyles in getIframeHtml

F-PROTON-WEBCL-001

Public snapshot: 26 Sep 2026. Status, releases and attribution belong to each source below; none is inferred from another record.

Recorded evidence

—score not recorded

ProtonMail/WebClientsReported fixProtonMail/WebClients

sanitize iframe bodyClasses and bodyStyles in getIframeHtml

fixed in public source; rollout not reverified

details

Finding IDs: F-PROTON-WEBCL-001
Status: fixed in public source; rollout not reverified
Reported via: security contact
Note: reviewed source escapes bodyClasses and bodyStyles with escapeHTMLAttribute before HTML attribute insertion. the previously cited c65861cab0a3 commit changes VPN retention-policy settings, not this renderer. prior fix-date, release and production-rollout claims are not supported by that commit and are withdrawn pending separate evidence.

F-PROTON-WEBCL-001: Code / markup injection. Unescaped class/style attribute values enter generated iframe HTML. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-PROTON-WEBCL-001

Security area (1seal assessment): Semantics. The inspected mail renderer escapes class/style attribute data before HTML insertion. This supports a data-to-markup boundary classification, not the previously recorded fix date or production rollout. Reviewed 21 Sep 2026.

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How this page groups evidence

This identifier groups recorded evidence; it is not an additional CVE, independent-vulnerability count or guarantee of vendor confirmation. Fixed code, released versions, attribution and independent discovery are distinct claims. Absent metadata means not recorded, not disproved. Counting rules.