CVE-2021-47334: misc/libmasm/module: Fix two use after free in ibmasm_init_one
Vulnerability summary
CVE-2021-47334 is a high (CVSS 7.8) Use After Free vulnerability in linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 20.3% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 6 · Related 6Timeline
- 21-05-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: misc/libmasm/module: Fix two use after free in ibmasm_init_one In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively. In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev. My patch add a "error_init_remote" label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
20%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.28% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu88 products
- linuxAll versions (No fix recorded) | < 4.15.0-156.163 | < 5.4.0-88.99
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1111.118 | < 5.4.0-1057.60
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < 1512e7dc5eb08b7d92a12e2bfcd9cb8c4a1ec069 | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < 29ba8e2ba89ee2862a26d91204dd5fe77ceee25a | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < 5b06ca113bf197aab2ab61288f42506e0049fbab | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < 481a76d4749ee3a27f902ba213fdcbb4bb39720e | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < 38660031e80eaa6cc9370b031c180612f414b00d | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < b9c87ce3bc6331f82811a8cf8e930423c22523a3 | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < ef1067d2baa847d53c9988510d99fb494de4d12c | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < a7268e8a227d5a4f0bd1584f556246b0224ab274 | ≥ 736ce43295682d060f2b93624b4a339f9af6aab1, < 7272b591c4cb9327c43443f67b8fbae7657dd9ae | 2.6.16
- linux_kernel< 4.4.276 | ≥ 4.5, < 4.9.276 | ≥ 4.10, < 4.14.240 | ≥ 4.15, < 4.19.198 | ≥ 4.20, < 5.4.134 | ≥ 5.5, < 5.10.52 | ≥ 5.11, < 5.12.19 | ≥ 5.13, < 5.13.4
Debian1 product
- linux< 5.14.6-1
3 vendors · 91 products
