CVE-2020-15706: canonical ubuntu_linux Race Condition
CVSS: 6.4v3.1MediumModified
AliasesALPINE-CVE-2020-15706UBUNTU-CVE-2020-15706DEBIAN-CVE-2020-15706
Published 29-07-2020Last modified 16-09-2024
Vulnerability summary
CVE-2020-15706 is a medium (CVSS 6.4) Race Condition vulnerability in canonical ubuntu_linux. EPSS estimates a 0.98% chance of exploitation in the next 30 days, higher than 61.4% of scored vulnerabilities.
CVSS score
6.4/10
010
Medium · v3.1 (CVE.org)EPSS score
0.98%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 22 · Related 11DSA-4735-1MGASA-2021-0315OPENSUSE-SU-2020:1168-1OPENSUSE-SU-2020:1169-1OPENSUSE-SU-2024:10824-1RHSA-2020:3216RHSA-2020:3217RHSA-2020:3223RHSA-2020:3227RHSA-2020:3271RHSA-2020:3273RHSA-2020:3274RHSA-2020:3275RHSA-2020:3276SUSE-SU-2020:14440-1SUSE-SU-2020:2073-1SUSE-SU-2020:2074-1SUSE-SU-2020:2076-1SUSE-SU-2020:2077-1SUSE-SU-2020:2078-1SUSE-SU-2020:2079-1USN-4432-1
Timeline
- 29-07-2020PublishedVulnerability first disclosed.
- 16-09-2024Last modifiedVulnerability information updated.
Description
GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing, leading to arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and prior versions.
CVSS metrics
6 scores · 5 sources · 2 versionsMedium 6.4Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:HSourcesAll 5 agree
- OSV · AlpineEcosystem advisory · calculated6.4MediumCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated6.4MediumCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated6.4MediumCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- NVDNIST6.4MediumCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Medium 4.4Preferred score · NVD (NIST)
AV:L/AC:M/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
0.98%
Chance of exploitation in the next 30 days
Percentile
61%
Versus all other CVEs
30-day change
0.00 pp
From 0.98% on 18-09-2026
18-09-202618-10-2026
EPSS score0.98%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')The 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
Microsoft6 products
- windows_10na | 1607 | 1709 | 1803 | 1809 | 1903 | 1909 | 2004
- windows_8.1na
- windows_rt_8.1na
- windows_server_2012na | r2
- windows_server_2016na | 1903 | 1909 | 2004
Ubuntu4 products
- grub2< 2.02~beta2-9ubuntu1.20 | < 2.02~beta2-36ubuntu3.26 | < 2.02-2ubuntu8.16 | < 2.04-1ubuntu26.1
- grub2-signed< 1.34.22 | < 1.66.26 | < 1.93.18 | < 1.142.3
- grub2-unsignedAll versions (No fix recorded)
- grub2 in ubuntu≥ 20.04 LTS, < 2.04-1ubuntu26.1 | ≥ 18.04 LTS, < 2.02-2ubuntu8.16 | ≥ 16.04 LTS, < 2.02~beta2-36ubuntu3.26 | ≥ 14.04 ESM, < 2.02~beta2-9ubuntu1.20
Redhat3 products
Debian2 products
- grub2< 2.04-9
- debian_linuxEOL10.0
Alpine1 product
- grub< 2.06-r0
Canonical1 product
- ubuntu_linuxEOL14.04 | 16.04 | 18.04 | 20.04
Gnu1 product
- grub2≤ 2.04
Opensuse1 product
- leapEOL15.1 | 15.2
Suse1 product
- suse_linux_enterprise_server11 | 12 | 15
9 vendors · 20 products
References
23 links- www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/X Refsource CONFIRMREPORTThird Party Advisory
- wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypassVendor AdvisoryX Refsource UBUNTUREPORTThird Party Advisory
www.debian.org/security/2020-GRUB-UEFI-SecureBootVendor AdvisoryX Refsource DEBIANThird Party Advisory
portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011X Refsource CONFIRMPatchThird Party AdvisoryVendor Advisory- access.redhat.com/security/vulnerabilities/grub2bootloaderVendor AdvisoryX Refsource REDHATThird Party Advisory
- www.suse.com/c/suse-addresses-grub2-secure-boot-issue/Vendor AdvisoryX Refsource SUSEThird Party Advisory
- www.openwall.com/lists/oss-security/2020/07/29/3X Refsource CONFIRMREPORTMailing ListThird Party Advisory
- lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.htmlX Refsource CONFIRMREPORTIssue TrackingVendor Advisory
Show all 23 references
- lists.opensuse.org/opensuse-security-announce/2020-08/msg00017.htmlVendor AdvisoryX Refsource SUSEBroken LinkMailing ListThird Party Advisory
- lists.opensuse.org/opensuse-security-announce/2020-08/msg00016.htmlVendor AdvisoryX Refsource SUSEBroken LinkMailing ListThird Party Advisory
