fix: add usb permission to ledger iframe allow attribute #39082

cloudonshore · 2026-01-07T23:09:11Z

Description

Adds usb to the iframe permissions policy for the Ledger bridge iframe.

The Ledger iframe bridge (ledger-iframe-bridge) bundles both @ledgerhq/hw-transport-webhid and @ledgerhq/hw-transport-webusb. When certain code paths touch WebUSB APIs (e.g., during device enumeration, transport reconnection, or EIP-712 signing fallback), it fails with:

"Failed to execute 'getDevices' on 'USB': Access to the feature 'usb' is disallowed by permissions policy"

This commonly manifests during the internal MetaMask swap & bridge transactions.

The fix adds usb to the existing hid permission on the iframe's allow attribute.

Changelog

CHANGELOG entry: Fixed Ledger hardware wallet connection failures during swap transactions

Related issues

Fixes: #36513

Manual testing steps

Connect a Ledger hardware wallet via USB
Open the Ethereum app on the Ledger device
Initiate a swap transaction in MetaMask, especially on a wallet with very low ETH balance (forcing gasless transaction)
Verify the transaction signing completes without hanging or USB permission errors

Screenshots/Recordings

Before

NOTWORKINGSWAP.mov

After

WORKINGSWAP.mov

Pre-merge author checklist

I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
I've completed the PR template to the best of my ability
I’ve included tests if applicable
I’ve documented my code using JSDoc format if applicable
I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

Note

Allows the Ledger iframe to access WebUSB by expanding its permissions policy.

Updates app/offscreen/ledger.ts to set iframe.allow to hid; usb for https://metamask.github.io/ledger-iframe-bridge/9.0.1/, preventing "usb disallowed by permissions policy" errors during device interactions

^{Written by Cursor Bugbot for commit c3c36b8. This will update automatically on new commits. Configure here.}

github-actions · 2026-01-07T23:09:23Z

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

cloudonshore · 2026-01-07T23:11:46Z

I have read the CLA Document and I hereby sign the CLA

metamaskbotv2 · 2026-01-07T23:52:04Z

Builds ready [01c321c]

builds: chrome, firefox
builds (beta): chrome, firefox
builds (flask): chrome, firefox
builds (test): chrome, firefox
builds (test-flask): chrome, firefox
bundle size: Bundle Size Stats
user-actions-benchmark: User Actions Stats
storybook: Storybook
typescript migration: Dashboard
all artifacts
bundle viz:
- background: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
- common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
- ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18
- content-script: 0
- offscreen: 0

UI Startup Metrics (1311 ± 110 ms)

Platform	BuildType	Page	Metric	Mean (ms)	Min (ms)	Max (ms)	Std Dev (ms)	P 75 (ms)	P 95 (ms)
Chrome	Browserify	Standard Home	uiStartup	1311	1071	1647	110	1388	1481
			load	1095	882	1340	98	1166	1224
			domContentLoaded	1090	877	1332	97	1161	1216
			domInteractive	29	16	111	22	25	92
			firstPaint	175	66	1187	180	189	305
			backgroundConnect	220	199	260	12	224	252
			firstReactRender	15	9	36	4	17	22
			getState	38	18	86	13	44	70
			initialActions	1	0	7	1	1	2
			loadScripts	877	680	1129	97	948	1015
			setupStore	13	7	35	5	13	23
			numNetworkReqs	18	11	76	17	11	68
	Browserify	Power User Home	uiStartup	1814	1431	2397	187	1909	2163
			load	1054	872	1389	120	1156	1242
			domContentLoaded	1044	864	1371	119	1147	1233
			domInteractive	30	17	121	23	26	106
			firstPaint	174	66	1384	173	208	305
			backgroundConnect	245	202	618	84	233	498
			firstReactRender	15	11	28	2	15	19
			getState	172	131	321	33	189	236
			initialActions	1	0	2	1	1	1
			loadScripts	832	669	1165	119	938	1027
			setupStore	17	9	41	9	18	36
			numNetworkReqs	66	52	208	21	62	114
	Webpack	Standard Home	uiStartup	822	666	1139	83	873	969
			load	662	592	916	71	711	795
			domContentLoaded	657	588	913	71	706	789
			domInteractive	26	16	96	18	23	80
			firstPaint	105	61	342	56	109	233
			backgroundConnect	22	6	112	24	30	87
			firstReactRender	15	10	32	4	17	25
			getState	34	15	142	17	44	61
			initialActions	1	0	4	1	1	2
			loadScripts	654	586	910	70	704	780
			setupStore	13	7	51	8	14	31
			numNetworkReqs	17	11	74	16	11	64
	Webpack	Power User Home	uiStartup	1245	976	1821	172	1292	1644
			load	727	602	1040	93	760	899
			domContentLoaded	721	595	1036	93	753	892
			domInteractive	31	18	152	27	26	106
			firstPaint	126	65	458	69	162	261
			backgroundConnect	92	7	671	151	107	576
			firstReactRender	16	12	28	2	17	19
			getState	149	133	209	13	153	172
			initialActions	1	0	7	1	1	1
			loadScripts	718	592	1028	92	749	885
			setupStore	16	10	57	9	14	38
			numNetworkReqs	66	52	209	23	62	123
Firefox	Browserify	Standard Home	uiStartup	1435	1123	2129	212	1522	1921
			load	1141	938	1713	136	1208	1383
			domContentLoaded	1140	938	1713	137	1208	1383
			domInteractive	70	32	224	39	92	144
			firstPaint	-	-	-	-	-	-
			backgroundConnect	62	21	366	57	84	181
			firstReactRender	13	10	38	4	13	20
			getState	12	6	137	14	11	23
			initialActions	1	0	7	1	2	2
			loadScripts	1104	923	1686	121	1163	1306
			setupStore	22	5	808	81	13	51
			numNetworkReqs	20	9	81	19	14	76
	Browserify	Power User Home	uiStartup	2599	1509	3657	575	3066	3365
			load	1671	980	2747	557	2234	2564
			domContentLoaded	1670	980	2746	557	2234	2563
			domInteractive	89	33	370	74	94	276
			firstPaint	-	-	-	-	-	-
			backgroundConnect	402	27	1231	445	989	1194
			firstReactRender	20	12	66	9	21	28
			getState	117	76	387	41	127	186
			initialActions	2	1	4	1	2	3
			loadScripts	1349	961	2415	406	1353	2361
			setupStore	55	5	1116	154	43	179
			numNetworkReqs	75	52	164	29	87	143
	Webpack	Standard Home	uiStartup	1554	1232	2553	221	1623	2026
			load	1315	1076	2355	185	1372	1561
			domContentLoaded	1315	1076	2354	185	1372	1561
			domInteractive	72	28	191	40	105	138
			firstPaint	-	-	-	-	-	-
			backgroundConnect	55	20	198	41	64	147
			firstReactRender	14	11	26	3	15	24
			getState	15	8	95	10	16	28
			initialActions	1	0	3	1	2	2
			loadScripts	1282	1063	2331	175	1321	1503
			setupStore	16	5	114	19	15	63
			numNetworkReqs	20	9	85	20	13	76
	Webpack	Power User Home	uiStartup	2823	1769	4344	602	3274	3755
			load	2054	1188	3296	576	2551	2842
			domContentLoaded	2054	1188	3295	576	2551	2841
			domInteractive	95	27	1291	153	81	326
			firstPaint	-	-	-	-	-	-
			backgroundConnect	333	22	1330	386	343	1196
			firstReactRender	21	12	154	19	22	28
			getState	131	74	1149	110	154	211
			initialActions	3	0	90	9	2	3
			loadScripts	1787	1174	3042	495	2242	2617
			setupStore	62	4	1089	178	22	210
			numNetworkReqs	70	42	163	28	94	123

📊 Page Load Benchmark Results

Current Commit: 01c321c | Date: 1/7/2026

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

pageLoadTime-> current mean value: 1.03s (±42ms) 🟡 | historical mean value: 1.04s ⬇️ (historical data)
domContentLoaded-> current mean value: 717ms (±39ms) 🟢 | historical mean value: 729ms ⬇️ (historical data)
firstContentfulPaint-> current mean value: 75ms (±11ms) 🟢 | historical mean value: 79ms ⬇️ (historical data)

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.03s	42ms	1000ms	1.33s	1.08s	1.33s
domContentLoaded	717ms	39ms	693ms	999ms	753ms	999ms
firstPaint	75ms	11ms	60ms	164ms	84ms	164ms
firstContentfulPaint	75ms	11ms	60ms	164ms	84ms	164ms
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

Bundle size diffs [🚨 Warning! Bundle size has increased!]

background: 58 Bytes (0%)
ui: 0 Bytes (0%)
common: 20 Bytes (0%)

metamaskbotv2 · 2026-01-08T01:03:49Z

Builds ready [c3c36b8]

builds: chrome, firefox
builds (beta): chrome, firefox
builds (flask): chrome, firefox
builds (test): chrome, firefox
builds (test-flask): chrome, firefox
bundle size: Bundle Size Stats
user-actions-benchmark: User Actions Stats
storybook: Storybook
typescript migration: Dashboard
all artifacts
bundle viz:
- background: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
- common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
- ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18
- content-script: 0
- offscreen: 0

UI Startup Metrics (1291 ± 112 ms)

Platform	BuildType	Page	Metric	Mean (ms)	Min (ms)	Max (ms)	Std Dev (ms)	P 75 (ms)	P 95 (ms)
Chrome	Browserify	Standard Home	uiStartup	1291	1033	1558	112	1359	1454
			load	1084	876	1332	101	1151	1234
			domContentLoaded	1078	872	1325	101	1147	1226
			domInteractive	26	15	94	17	21	77
			firstPaint	145	65	1106	115	182	306
			backgroundConnect	217	200	248	10	221	239
			firstReactRender	14	8	25	3	15	22
			getState	38	19	126	14	43	63
			initialActions	1	0	9	1	1	2
			loadScripts	867	669	1117	101	930	1025
			setupStore	12	7	27	4	14	22
			numNetworkReqs	17	11	69	15	11	63
	Browserify	Power User Home	uiStartup	1785	1412	2383	193	1888	2154
			load	1042	871	1338	116	1137	1246
			domContentLoaded	1031	862	1331	115	1128	1240
			domInteractive	28	16	116	20	25	89
			firstPaint	167	66	1299	167	200	249
			backgroundConnect	243	200	670	80	234	475
			firstReactRender	14	11	26	2	15	21
			getState	183	133	273	29	205	231
			initialActions	1	0	3	1	1	2
			loadScripts	818	667	1127	110	913	1017
			setupStore	19	7	58	11	27	38
			numNetworkReqs	67	55	209	21	64	116
	Webpack	Standard Home	uiStartup	796	644	1172	96	841	988
			load	656	568	1087	99	697	877
			domContentLoaded	650	561	1082	98	693	874
			domInteractive	25	15	94	19	21	86
			firstPaint	104	56	339	53	125	201
			backgroundConnect	23	6	124	26	31	91
			firstReactRender	15	10	36	4	15	24
			getState	34	14	147	24	40	68
			initialActions	1	0	7	1	1	2
			loadScripts	647	559	1080	98	690	864
			setupStore	11	6	43	6	13	24
			numNetworkReqs	18	11	81	18	11	69
	Webpack	Power User Home	uiStartup	1301	1011	2107	218	1360	1800
			load	736	614	940	91	791	913
			domContentLoaded	729	608	935	90	785	907
			domInteractive	32	18	160	28	27	109
			firstPaint	119	65	344	61	143	249
			backgroundConnect	110	8	637	170	128	546
			firstReactRender	17	13	25	2	17	20
			getState	149	70	188	14	157	174
			initialActions	1	0	2	0	1	1
			loadScripts	726	606	932	89	782	900
			setupStore	14	9	42	6	14	32
			numNetworkReqs	68	53	228	28	63	124
Firefox	Browserify	Standard Home	uiStartup	1367	1063	1867	184	1496	1789
			load	1085	905	1544	121	1170	1274
			domContentLoaded	1084	905	1544	121	1164	1274
			domInteractive	66	30	211	37	85	137
			firstPaint	-	-	-	-	-	-
			backgroundConnect	57	19	296	49	77	161
			firstReactRender	12	9	44	4	12	17
			getState	16	6	370	39	10	46
			initialActions	1	0	2	0	1	2
			loadScripts	1048	891	1444	102	1104	1203
			setupStore	14	5	113	15	12	47
			numNetworkReqs	19	9	83	19	13	77
	Browserify	Power User Home	uiStartup	2603	1549	4263	641	3085	3432
			load	1760	967	2871	618	2312	2652
			domContentLoaded	1760	966	2871	617	2311	2652
			domInteractive	76	33	283	57	84	210
			firstPaint	-	-	-	-	-	-
			backgroundConnect	400	22	1393	445	465	1221
			firstReactRender	19	12	61	7	22	28
			getState	117	38	209	27	130	170
			initialActions	2	0	3	1	2	3
			loadScripts	1447	950	2553	494	2048	2376
			setupStore	40	5	1092	112	30	103
			numNetworkReqs	75	44	154	29	92	141
	Webpack	Standard Home	uiStartup	1572	1306	3144	232	1645	1939
			load	1314	1116	2892	196	1375	1545
			domContentLoaded	1313	1116	2892	196	1375	1545
			domInteractive	93	28	1520	151	113	141
			firstPaint	-	-	-	-	-	-
			backgroundConnect	54	20	152	34	60	135
			firstReactRender	15	11	57	6	15	25
			getState	21	8	172	29	17	103
			initialActions	1	0	3	1	2	2
			loadScripts	1283	1101	2866	189	1315	1495
			setupStore	20	6	135	27	15	107
			numNetworkReqs	20	9	81	20	13	77
	Webpack	Power User Home	uiStartup	2888	1694	3995	614	3342	3667
			load	2110	1182	3022	614	2625	2890
			domContentLoaded	2109	1182	3021	614	2625	2890
			domInteractive	126	29	1110	209	89	474
			firstPaint	-	-	-	-	-	-
			backgroundConnect	392	25	1382	433	424	1281
			firstReactRender	20	13	81	7	23	27
			getState	133	76	1355	128	133	194
			initialActions	2	1	3	1	2	3
			loadScripts	1804	1158	2797	532	2382	2644
			setupStore	62	6	1298	180	23	225
			numNetworkReqs	70	40	171	33	65	158

📊 Page Load Benchmark Results

Current Commit: c3c36b8 | Date: 1/8/2026

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

pageLoadTime-> current mean value: 1.02s (±39ms) 🟡 | historical mean value: 1.04s ⬇️ (historical data)
domContentLoaded-> current mean value: 712ms (±36ms) 🟢 | historical mean value: 727ms ⬇️ (historical data)
firstContentfulPaint-> current mean value: 75ms (±12ms) 🟢 | historical mean value: 79ms ⬇️ (historical data)

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.02s	39ms	999ms	1.32s	1.04s	1.32s
domContentLoaded	712ms	36ms	690ms	989ms	728ms	989ms
firstPaint	75ms	12ms	60ms	184ms	88ms	184ms
firstContentfulPaint	75ms	12ms	60ms	184ms	88ms	184ms
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

Bundle size diffs [🚨 Warning! Bundle size has increased!]

background: 58 Bytes (0%)
ui: 0 Bytes (0%)
common: 20 Bytes (0%)

Gudahtt

LGTM!

dawnseeker8

LGTM

fix: add usb permission to ledger iframe allow attribute

5c1e446

cloudonshore temporarily deployed to pr-comment January 7, 2026 23:09 — with GitHub Actions Inactive

metamaskbot added team-swaps-and-bridge Swaps and Bridge team INVALID-PR-TEMPLATE PR's body doesn't match template labels Jan 7, 2026

github-actions bot added the size-XS label Jan 7, 2026

Merge branch 'main' into ledger-add-usb-permission

35da139

cloudonshore temporarily deployed to pr-comment January 7, 2026 23:11 — with GitHub Actions Inactive

metamaskbot removed the INVALID-PR-TEMPLATE PR's body doesn't match template label Jan 7, 2026

Merge branch 'main' into ledger-add-usb-permission

01c321c

cloudonshore temporarily deployed to pr-comment January 7, 2026 23:19 — with GitHub Actions Inactive

cloudonshore temporarily deployed to pr-comment January 7, 2026 23:47 — with GitHub Actions Inactive

Merge branch 'main' into ledger-add-usb-permission

c3c36b8

cloudonshore temporarily deployed to pr-comment January 8, 2026 00:30 — with GitHub Actions Inactive

cloudonshore temporarily deployed to pr-comment January 8, 2026 00:59 — with GitHub Actions Inactive

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cloudonshore added this pull request to the merge queue Jan 9, 2026

Merged via the queue into main with commit 4f8bc81 Jan 9, 2026
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cloudonshore deleted the ledger-add-usb-permission branch January 9, 2026 03:14

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fix: add usb permission to ledger iframe allow attribute #39082

fix: add usb permission to ledger iframe allow attribute #39082

cloudonshore commented Jan 7, 2026 •

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Description

Changelog

Related issues

Manual testing steps

Screenshots/Recordings

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After

Pre-merge author checklist

Pre-merge reviewer checklist

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cloudonshore commented Jan 7, 2026 •

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