CVE-2021-47361: mcb: fix error handling in mcb_alloc_bus()
Vulnerability summary
CVE-2021-47361 is a high (CVSS 7.8) Use After Free vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 15.5% 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 8 · Related 8Timeline
- 21-05-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: mcb: fix error handling in mcb_alloc_bus() There are two bugs: 1) If ida_simple_get() fails then this code calls put_device(carrier) but we haven't yet called get_device(carrier) and probably that leads to a use after free. 2) After device_initialize() then we need to use put_device() to release the bus. This will free the internal resources tied to the device and call mcb_free_bus() which will free the rest.
CVSS metrics
4 scores · 3 sources · 2 versions- 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
0.24%
Chance of exploitation in the next 30 days
Percentile
16%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.24% 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.
Ubuntu86 products
- linux< 4.15.0-163.171 | < 5.4.0-91.102
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.15.0-1116.123 | < 5.4.0-1060.63
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 8a558261fa57a6deefb0925ab1829f698b194aea | ≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 115b07d9f47e3996430b8f2007edd9768e1f807f | ≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 66f74ba9be9daf9c47fface6af3677f602774f6b | ≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 7751f609eadf36b1f53712bae430019c53a16eb0 | ≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 91e4ad05bf18322b5921d1a6c9b603f6eb1694f0 | ≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 9fc198f415dee070a1de957bb5bf5921d8df3499 | ≥ 18d28819809909c3f24bb72183a901c5e332a63d, < 25a1433216489de4abc889910f744e952cb6dbae | 4.7
- linux_kernel≥ 4.7, < 4.9.285 | ≥ 4.10, < 4.14.249 | ≥ 4.15, < 4.19.209 | ≥ 4.20, < 5.4.150 | ≥ 5.5, < 5.10.70 | ≥ 5.11, < 5.14.9 | 5.15:rc1 | 5.15:rc2
Debian1 product
- linux< 5.14.9-1
3 vendors · 89 products
