CVE-2021-37159: debian debian_linux Double Free
Vulnerability summary
CVE-2021-37159 is a medium (CVSS 6.4) Double Free vulnerability in debian debian_linux. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 33.3% of scored vulnerabilities.
Not severe (CVSS 6.4, physical access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 31 · Related 27Timeline
- 21-07-2021PublishedVulnerability first disclosed.
- 08-10-2026Last modifiedVulnerability information updated.
Description
hso_free_net_device in drivers/net/usb/hso.c in the Linux kernel through 5.13.4 calls unregister_netdev without checking for the NETREG_REGISTERED state, leading to a use-after-free and a double free.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated6.4MediumCVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated6.4MediumCVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.39%
Chance of exploitation in the next 30 days
Percentile
33%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.39% 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 cause- CWE-415Double FreeThe product calls free() twice on the same memory address.
- CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Affected systems
Known conditions: physical access, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu62 products
- linux< 3.13.0-199.250 | < 4.4.0-223.256 | < 4.15.0-163.171 | < 5.4.0-91.102
- linux-aws< 4.4.0-1103.108 | < 4.4.0-1139.153 | < 4.15.0-1116.123 | < 5.4.0-1060.63
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11< 5.11.0-1019.20~20.04.1
- linux-aws-5.3All versions (No fix recorded)
Oracle3 products
Debian2 products
- linux< 5.14.6-1
- debian_linuxEOL9.0
Linux1 product
- linux_kernel≤ 5.13.4
4 vendors · 68 products
References
21 links
- security.netapp.com/advisory/ntap-20210819-0003/Third Party Advisory
