CVE-2020-25656: debian debian_linux Use After Free

Modified

AliasesUBUNTU-CVE-2020-25656DEBIAN-CVE-2020-25656

Published 02-12-2020Last modified 04-08-2024

Vulnerability summary

CVE-2020-25656 is a medium (CVSS 4.1) Use After Free vulnerability in debian debian_linux. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 38.2% of scored vulnerabilities. 2 public exploits are recorded.

Priority

Routine

Not severe (CVSS 4.1, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?

CVSS score

4.1/10

010

Medium · v3.1 (NVD)

EPSS score

0.44%

0%100%

Low · 0.00 pp in 30 days

KEVNot listedNot listed by any tracked catalog.

RansomwareNot flaggedNo ransomware use recorded.

Public exploits2reference

Timeline

02-12-2020
PublishedVulnerability first disclosed.
04-08-2024
Last modifiedVulnerability information updated.

Description

A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality.

CVSS metrics

4 scores · 3 sources · 2 versions

v3.14.1v2.01.9

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.44% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs

CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

2 found

referenceUnverified
Exploit Reference (bugzilla.redhat.com)
Maturity: unknown
referenceUnverified
Exploit Reference (lkml.org)
Maturity: unknown

Weaknesses

CWE · root cause

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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

Version check

Known conditions: local access, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu46 products

linuxAll versions (No fix recorded) | < 4.4.0-198.230 | < 4.15.0-129.132 | < 5.4.0-59.65
linux-aws< 4.4.0-1083.87 | < 4.4.0-1119.133 | < 4.15.0-1091.96 | < 5.4.0-1034.35
linux-aws-5.0All versions (No fix recorded)
linux-aws-5.3All versions (No fix recorded)
linux-aws-5.4< 5.4.0-1034.35~18.04.1

linux-aws-fips< 4.15.0-2034.35 | All versions (No fix recorded) | < 5.4.0-1069.73+fips2
linux-aws-hwe< 4.15.0-1091.96~16.04.1
linux-azure< 4.15.0-1103.114~14.04.1 | < 4.15.0-1103.114~16.04.1 | All versions (No fix recorded) | < 5.4.0-1035.36
linux-azure-4.15< 4.15.0-1103.114
linux-azure-5.3All versions (No fix recorded)
linux-azure-5.4< 5.4.0-1035.36~18.04.1
linux-azure-edgeAll versions (No fix recorded)
linux-azure-fde-5.15< 5.15.0-1114.123~20.04.1
linux-azure-fips< 4.15.0-2016.18 | All versions (No fix recorded) | < 5.4.0-1073.76+fips1
linux-dell300x< 4.15.0-1010.14
linux-fips< 4.4.0-1052.58 | All versions (No fix recorded) | < 4.15.0-1049.56
linux-gcp< 4.15.0-1091.104~16.04.1 | All versions (No fix recorded) | < 5.4.0-1033.35
linux-gcp-4.15< 4.15.0-1091.104
linux-gcp-5.3All versions (No fix recorded)
linux-gcp-5.4< 5.4.0-1033.35~18.04.1
linux-gcp-edgeAll versions (No fix recorded)
linux-gcp-fipsAll versions (No fix recorded) | < 5.4.0-1067.71~20.04.1
linux-gke-4.15< 4.15.0-1077.82
linux-gke-5.4< 5.4.0-1033.35~18.04.1
linux-gkeop-5.4< 5.4.0-1008.9~18.04.1
linux-hwe< 4.15.0-129.132~16.04.1 | All versions (No fix recorded)
linux-hwe-5.4< 5.4.0-59.65~18.04.1
linux-hwe-5.8< 5.8.0-44.50~20.04.1
linux-hwe-edgeAll versions (No fix recorded)
linux-intel-iot-realtimeAll versions (No fix recorded)
linux-kvm< 4.4.0-1085.94 | < 4.15.0-1082.84 | < 5.4.0-1031.32
linux-lts-xenial< 4.4.0-198.230~14.04.1
linux-oemAll versions (No fix recorded)
linux-oem-5.6< 5.6.0-1050.54
linux-oracle< 4.15.0-1062.68~16.04.1 | < 4.15.0-1062.68 | < 5.4.0-1034.36
linux-oracle-5.0All versions (No fix recorded)
linux-oracle-5.3All versions (No fix recorded)
linux-oracle-5.4< 5.4.0-1034.36~18.04.1
linux-raspi< 5.4.0-1026.29
linux-raspi-5.4< 5.4.0-1026.29~18.04.1
linux-raspi-realtimeAll versions (No fix recorded)
linux-raspi2< 4.4.0-1143.153 | < 4.15.0-1077.82 | All versions (No fix recorded)
linux-realtimeAll versions (No fix recorded)
linux-riscv< 5.4.0-40.45
linux-riscv-5.8< 5.8.0-17.19~20.04.1
linux-snapdragon< 4.4.0-1147.157 | < 4.15.0-1094.103

Show all 46

Debian2 products

linux< 5.9.6-1
debian_linuxEOL9.0

Linux1 product

linux_kernel< 5.10 | 5.10:rc1

Redhat1 product

enterprise_linuxEOL7.0 | 8.0

Starwindsoftware1 product

starwind_virtual_sanv8:build12533 | v8:build12658 | v8:build12859 | v8:build13170 | v8:build13586 | v8:build13861

5 vendors · 51 products

References

15 links

bugzilla.redhat.com/show_bug.cgi?id=1888726ExploitIssue TrackingPatchThird Party Advisory
lkml.org/lkml/2020/10/29/528Mailing ListPatchThird Party Advisory
lkml.org/lkml/2020/10/16/84ExploitMailing ListThird Party Advisory
lists.debian.org/debian-lts-announce/2020/12/msg00015.htmlMailing ListThird Party Advisory
lists.debian.org/debian-lts-announce/2020/12/msg00027.htmlMailing ListThird Party Advisory
www.starwindsoftware.com/security/sw-20210325-0006/Third Party Advisory
ubuntu.com/security/CVE-2020-25656REPORT
www.openwall.com/lists/oss-security/2020/10/16/1REPORT
ubuntu.com/security/notices/USN-4679-1Advisory
ubuntu.com/security/notices/USN-4680-1Advisory

Show all 15 references

ubuntu.com/security/notices/USN-4681-1Advisory
ubuntu.com/security/notices/USN-4751-1Advisory
www.cve.org/CVERecord?id=CVE-2020-25656REPORT
security-tracker.debian.org/tracker/CVE-2020-25656Advisory
nvd.nist.gov/vuln/detail/CVE-2020-25656OvalAdvisory