CVE-2018-20836: canonical ubuntu_linux
Modified
AliasesUBUNTU-CVE-2018-20836DEBIAN-CVE-2018-20836
Published 07-05-2019Last modified 05-08-2024
Vulnerability summary
CVE-2018-20836 is a high (CVSS 9.3) vulnerability in canonical ubuntu_linux. EPSS estimates a 5.09% chance of exploitation in the next 30 days, higher than 92.3% of scored vulnerabilities.
Priority
Prioritisesevere
Severe, CVSS 8.1 (NVD); no exploitation reported by the 5 checked sources; EPSS 5% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?CVSS score
9.3/10
010
High · v2.0 (NVD)EPSS score
5.09%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 26 · Related 18DLA-1884-1DLA-1885-1DSA-4495-1DSA-4497-1OPENSUSE-SU-2019:1716-1OPENSUSE-SU-2019:1757-1RHSA-2020:4060RHSA-2020:4062RHSA-2020:5656RHSA-2021:0019SUSE-SU-2019:14127-1SUSE-SU-2019:1823-1SUSE-SU-2019:1823-2SUSE-SU-2019:1829-1SUSE-SU-2019:1851-1SUSE-SU-2019:1852-1SUSE-SU-2019:1854-1SUSE-SU-2019:1855-1SUSE-SU-2019:1870-1SUSE-SU-2019:2069-1SUSE-SU-2019:2430-1SUSE-SU-2019:2450-1SUSE-SU-2020:1084-1SUSE-SU-2020:1118-1SUSE-SU-2020:1142-1USN-4076-1
Timeline
- 07-05-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
An issue was discovered in the Linux kernel before 4.20. There is a race condition in smp_task_timedout() and smp_task_done() in drivers/scsi/libsas/sas_expander.c, leading to a use-after-free.
CVSS metrics
5 scores · 3 sources · 3 versionsHigh 8.1Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
High 8.1Preferred score · OSV · Ubuntu (Ecosystem advisory) · calculated from vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesSingle source
High 9.3Preferred score · NVD (NIST)
AV:N/AC:M/Au:N/C:C/I:C/A:CSourcesSingle source
EPSS trend
Probability
5.09%
Chance of exploitation in the next 30 days
Percentile
92%
Versus all other CVEs
30-day change
No change 0.00 pp
From 5.09% on 04-10-2026
04-10-202603-11-2026
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
Version check
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu19 products
- linuxAll versions (No fix recorded) | < 4.4.0-157.185 | < 4.15.0-44.47
- linux-aws< 4.4.0-1054.58 | < 4.4.0-1090.101 | < 4.15.0-1032.34
- linux-aws-hwe< 4.15.0-1032.34~16.04.1
- linux-azure< 4.15.0-1037.39~14.04.2 | < 4.15.0-1037.39~16.04.1 | < 4.15.0-1037.39
- linux-azure-fdeAll versions (No fix recorded)
Netapp8 products
- active_iq_unified_manager≥ 9.5 (No fix recorded)
- hci_compute_nodena
- snapprotectna
- solidfire_\&_hci_management_nodena
- solidfire_\&_hci_storage_nodena
Debian2 products
- linux< 5.2.6-1
- debian_linuxEOL8.0 | 9.0 | 10.0
Canonical1 product
- ubuntu_linuxEOL16.04
F51 product
- traffix_signaling_delivery_controller5.0.0 | 5.1.0
Linux1 product
- linux_kernel< 3.16.72 | ≥ 3.17, < 3.18.140 | ≥ 3.19, < 4.4.180 | ≥ 4.5, < 4.9.175 | ≥ 4.10, < 4.14.118 | ≥ 4.15, < 4.19.42
Opensuse1 product
- leapEOL15.0 | 15.1
7 vendors · 33 products
References
18 links- github.com/torvalds/linux/commit/b90cd6f2b905905fb42671009dc0e27c310a16aeX Refsource MISCPatchVendor Advisory
- lists.opensuse.org/opensuse-security-announce/2019-07/msg00014.htmlVendor AdvisoryX Refsource SUSEMailing ListThird Party Advisory
- lists.opensuse.org/opensuse-security-announce/2019-07/msg00025.htmlVendor AdvisoryX Refsource SUSEMailing ListThird Party Advisory
Show all 18 references
- lists.debian.org/debian-lts-announce/2019/08/msg00016.htmlMailing ListX Refsource MLISTThird Party Advisory
- lists.debian.org/debian-lts-announce/2019/08/msg00017.htmlMailing ListX Refsource MLISTThird Party Advisory