1sealsemantic last-mile verification

Research / Finding

Telegram iOS: bridge exposed to iframes

F-TELEGRAM-WEBAPP-001

Read the full technical write-up →

Root cause, affected code and disclosure timeline.

At a glance

Conditions
A third-party iframe in a bot Web App can reach a bridge intended for the main frame.
What to do
Use a version containing the release-12.4 main-frame checks. The source-branch evidence does not verify rollout to every installed app.

1seal reading guide, reviewed 2026-09-25 against the linked records. Not a new vendor assessment or a device rollout check.

Fix and severity by source

Source assessments remain separate. Different CVSS versions are not a revision of one another. Code fixes, released versions and deployed updates are distinct evidence.

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

Read the evidence · View in research browse

Recorded evidence

—score not recorded
1SEAL-2026-0081SEAL advisoryTelegramMessenger/Telegram-iOS

Telegram iOS Web App bridge exposed to third-party iframes

Fixed in: release-12.4

Fix recordednot counted
details
Finding IDs
F-TELEGRAM-WEBAPP-001
Status
patched
CWE
CWE-863, CWE-346
Fixed in
release-12.4
Disclosure date
Recorded severity
medium

F-TELEGRAM-WEBAPP-001: Access control. A subframe can reach a bridge intended for the main frame. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-TELEGRAM-WEBAPP-001

Security area (1seal assessment): Authorization. A subframe can reach a bridge intended for the main frame. Reviewed 24 Sep 2026.

—score not recorded
TelegramMessenger/Telegram-iOSReported fixTelegramMessenger/Telegram-iOS

Telegram iOS Web App bridge exposed to third-party iframes

fixed publicly
details
Finding IDs
F-TELEGRAM-WEBAPP-001
Status
fixed publicly
Reported via
Telegram security contact
Note
public fix commit c5a0ad267cbd2a61a0d4548490f6af5521fa55df in release-12.4. see 1SEAL-2026-008.

F-TELEGRAM-WEBAPP-001: Access control. A subframe can reach a bridge intended for the main frame. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-TELEGRAM-WEBAPP-001

Security area (1seal assessment): Authorization. A subframe can reach a bridge intended for the main frame. Reviewed 24 Sep 2026.

Clarify or correct this record privately. The email subject includes the finding ID. For an existing case, continue the agreed private thread. Do not post unpublished vulnerability details in public issues. Research disclosure policy.

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.