Ledger Donjon disclosed a Tangem laser attack on July 9 that can reset a wallet card’s access code without knowing the old code or possessing a backup card. The researchers say the flaw affects all Tangem cards currently in circulation and cannot be fixed with a firmware update. This is not a remote hack, however: an attacker needs the physical card, a laboratory setup estimated at about $250,000, and advanced hardware-security expertise.
The practical response depends on physical control. If every card is still in your possession, the research alone is not a reason for an emergency transfer. If a card is lost or stolen, moving funds to a newly generated wallet is safer than assuming its access code will remain an effective barrier forever.
How the Tangem laser attack works
Ledger Donjon opened the chip package and aimed a nanosecond laser pulse at a precise area of the secure element. The pulse caused a fault during one firmware check, allowing the researchers to set the card’s access code to a value they controlled.
The attack did not require the previous code, a second card, or the normal recovery workflow. Disabling access-code recovery did not stop it either. Because Tangem cards do not have a firmware update mechanism, cards already in circulation cannot receive a software patch for this behavior.
That does not mean a criminal can attack a card through NFC, the Tangem app, or the internet. The chip must be physically removed and prepared, and the invasive procedure leaves visible damage. Tangem’s response also stresses the cost, specialist staff, and substantial preparation needed to reproduce the research.
Who actually needs to act
| Situation | Risk and what to do |
|---|---|
| All cards are under your control | The research creates no remote exposure. Keep backup cards physically separated and do not lend them to anyone. |
| One card is misplaced | Confirm whether it is truly lost. If someone else may have found it, prepare to move assets to a new wallet. |
| A card was stolen or stayed outside your control | Create a wallet with new keys and transfer funds using a card you still control. |
| The wallet protects a high-value or publicly attributable balance | Include a targeted physical lab attack in the threat model and keep a strict inventory of every card. |
What to do after losing a Tangem card
- Do not enter your seed phrase into an “urgent checker.” Publicity around the flaw is likely to attract phishing pages and fake support messages.
- Use a remaining card to prepare the transfer. If theft is plausible and the wallet holds meaningful funds, do not wait for the missing card to reappear.
- Create an entirely new wallet. Do not import the same seed phrase, because the missing card would still hold keys for that same wallet.
- Transfer and verify. Send a small test transaction first, then move the remaining assets and verify the destination addresses in a blockchain explorer.
- Store the new backup cards separately. Do not carry the full set together or leave it where someone can obtain prolonged, unnoticed access.
Changing the access code on a card you still own does not remotely revoke the missing card. Tangem stores access codes separately on each device. New keys and an on-chain transfer therefore matter more than changing a local code after a card has been stolen.
What the finding does not prove
- Tangem cards cannot be compromised remotely with this method.
- An ordinary finder cannot instantly open a card.
- The research does not report real-world thefts performed with laser fault injection.
- The lab attack does not replace more common risks such as phishing, seed-phrase exposure, malicious approvals, or malware on a connected device.
For a different wallet failure mode, see our coverage of the Ill Bloom weak-seed vulnerability. Ill Bloom concerns predictable wallet keys; the Tangem finding changes an access-code check on a physically captured card.
Our hot wallet vs. cold wallet security guide explains how physical custody, seed phrases, signing decisions, and connected-device malware fit into the broader threat model.
References
- Ledger Donjon. “Bypassing Tangem Card Security with a Laser Attack.” Ledger Donjon, July 9, 2026. Technical research.
- Tangem. “Our Comment on Ledger Donjon’s Latest Article.” Tangem, updated July 9, 2026. Vendor response.
- Tangem. “Lost Your Hardware Wallet? Here’s Exactly What to Do.” Tangem Learning Hub, accessed July 10, 2026. Lost-card guidance.
