CVE-2021-47323: watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff()
Vulnerability summary
CVE-2021-47323 is a high (CVSS 8.8) Use After Free vulnerability in linux. EPSS estimates a 1.16% chance of exploitation in the next 30 days, higher than 67.1% of scored vulnerabilities.
Not severe (CVSS 8.8, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 7 · Related 7Timeline
- 21-05-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff() This module's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
1.16%
Chance of exploitation in the next 30 days
Percentile
67%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.16% 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: network-reachable, 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≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 0015581a79bbf8e521f85dddb7d3e4a66b9f51d4 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < b4565a8a2d6bffb05bfbec11399d261ec16fe373 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 2aef07017fae21c3d8acea9656b10e3b9c0f1e04 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 522e75ed63f67e815d4ec0deace67df22d9ce78e | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7c56c5508dc20a6b133bc669fc34327a6711c24c | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < a173e3b62cf6dd3c4a0a10c8a82eedfcae81a566 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < b3c41ea5bc34d8c7b19e230d80e0e555c6f5057d | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < f0feab82f6a0323f54d85e8b512a2be64f83648a | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 90b7c141132244e8e49a34a4c1e445cce33e07f4 | 2.6.12
- 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
