CVE-2020-36557: linux linux_kernel
Vulnerability summary
CVE-2020-36557 is a medium (CVSS 5.1) vulnerability in linux linux_kernel. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 10.1% of scored vulnerabilities.
Not severe (CVSS 5.1, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 18 · Related 17Timeline
- 21-07-2022PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
A race condition in the Linux kernel before 5.6.2 between the VT_DISALLOCATE ioctl and closing/opening of ttys could lead to a use-after-free.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.1MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.1MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.20%
Chance of exploitation in the next 30 days
Percentile
10%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.20% 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-362Concurrent Execution using Shared Resource with Improper SynchronizationThe product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
- 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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: local access, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu54 products
- linuxAll versions (No fix recorded) | < 4.4.0-179.209 | < 4.15.0-99.100
- linux-aws< 4.4.0-1067.71 | < 4.4.0-1107.118 | < 4.15.0-1066.70
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
- linux-aws-5.13All versions (No fix recorded)
Debian1 product
- linux< 5.5.17-1
Linux1 product
- linux_kernel< 5.6.2
3 vendors · 56 products
References
5 links- cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.6.2X Refsource MISCREPORTPatchRelease NotesVendor Advisory
