CVE-2020-28974: A slab-out-of-bounds read in fbcon in the Linux kernel before 5.9.7 could be used by local attackers to read privileged information or poten
Noroxi assessment
Priority: Monitor (action score 20/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.51% (FIRST EPSS).
- Physical access to the device is required. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: linux (Debian:12) 5.9.9-1; linux (Debian:9) 4.9.246-1; linux-4.19 (Debian:9) 4.19.160-2~deb9u1.
- Mentioned 3 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to linux (Debian:12) 5.9.9-1; linux (Debian:9) 4.9.246-1; linux-4.19 (Debian:9) 4.19.160-2~deb9u1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
A slab-out-of-bounds read in fbcon in the Linux kernel before 5.9.7 could be used by local attackers to read privileged information or potentially crash the kernel, aka CID-3c4e0dff2095. This occurs because KD_FONT_OP_COPY in drivers/tty/vt/vt.c can be used for manipulations such as font height.
- BDU:2020-05544
- ALSA-2021:1578
- DLA-2483-1
- DLA-2494-1
- openSUSE-SU-2020:2161-1
- openSUSE-SU-2020:2193-1
- openSUSE-SU-2020:2260-1
- SUSE-SU-2020:3522-1
- SUSE-SU-2020:3713-1
- SUSE-SU-2020:3714-1
- SUSE-SU-2020:3715-1
- SUSE-SU-2020:3717-1
- SUSE-SU-2020:3718-1
- SUSE-SU-2020:3748-1
- SUSE-SU-2020:3766-1
- SUSE-SU-2020:3798-1
- SUSE-SU-2021:0434-1
- SUSE-SU-2021:0437-1
- SUSE-SU-2021:0438-1
- SUSE-SU-2021:0452-1
- Published
- Nov 20, 2020
- Updated
- Jun 16, 2026
- EPSS
- 0.5% · 43th percentile
- CWE
- CWE-125
Report tools
Action score
20
Monitor
Low priority for now.
- CVSS
- 20 / 40 · 5.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux9.0
- linux linux kernelbefore 5.9.7
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.9.9-1 | 5.9.9-1 |
| Debian:9 | linux | before 4.9.246-1 | 4.9.246-1 |
| Debian:9 | linux-4.19 | before 4.19.160-2~deb9u1 | 4.19.160-2~deb9u1 |
| openSUSE:Leap 15.1 | kernel-debug | before 4.12.14-lp151.28.87.2 | 4.12.14-lp151.28.87.2 |
| openSUSE:Leap 15.1 | kernel-default | before 4.12.14-lp151.28.87.2 | 4.12.14-lp151.28.87.2 |
| openSUSE:Leap 15.1 | kernel-docs | before 4.12.14-lp151.28.87.1 | 4.12.14-lp151.28.87.1 |
| openSUSE:Leap 15.1 | kernel-kvmsmall | before 4.12.14-lp151.28.87.2 | 4.12.14-lp151.28.87.2 |
| openSUSE:Leap 15.1 | kernel-obs-build | before 4.12.14-lp151.28.87.2 | 4.12.14-lp151.28.87.2 |
| openSUSE:Leap 15.1 | kernel-obs-qa | before 4.12.14-lp151.28.87.2 | 4.12.14-lp151.28.87.2 |
| openSUSE:Leap 15.1 | kernel-source | before 4.12.14-lp151.28.87.1 | 4.12.14-lp151.28.87.1 |
| openSUSE:Leap 15.1 | kernel-syms | before 4.12.14-lp151.28.87.1 | 4.12.14-lp151.28.87.1 |
| openSUSE:Leap 15.1 | kernel-vanilla | before 4.12.14-lp151.28.87.2 | 4.12.14-lp151.28.87.2 |
| openSUSE:Leap 15.2 | kernel-debug | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-default | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-default-base | before 5.3.18-lp152.57.1.lp152.8.17.1 | 5.3.18-lp152.57.1.lp152.8.17.1 |
| openSUSE:Leap 15.2 | kernel-default-base | before 5.3.18-lp152.54.1.lp152.8.12.1 | 5.3.18-lp152.54.1.lp152.8.12.1 |
| openSUSE:Leap 15.2 | kernel-docs | before 5.3.18-lp152.54.2 | 5.3.18-lp152.54.2 |
| openSUSE:Leap 15.2 | kernel-kvmsmall | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-obs-build | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-obs-qa | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-preempt | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-source | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| openSUSE:Leap 15.2 | kernel-syms | before 5.3.18-lp152.54.1 | 5.3.18-lp152.54.1 |
| SUSE:HPE Helion OpenStack 8 | kernel-default | before 4.4.180-94.138.1 | 4.4.180-94.138.1 |
+61
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
Published before and after this one in the same product
- ← EarlierCVE-2020-28915Nov 18, 2020 · A buffer over-read (at the framebuffer layer) in the fbcon code in the Linux kernel before 5.8.15 could be used by local attackers to read k23Monitor
- ← EarlierCVE-2020-28941Nov 19, 2020 · An issue was discovered in drivers/accessibility/speakup/spk_ttyio.c in the Linux kernel through 5.9.9.22Monitor
- Later →CVE-2020-12351Nov 23, 2020 · Improper input validation in BlueZ may allow an unauthenticated user to potentially enable escalation of privilege via adjacent access.37Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:kernel-tools-libs-devel | 4.18.0-305.el8 · AlmaLinux:8 | Package registry (OSV) |
| debian:linux | 5.9.9-1 · Debian:12 | Package registry (OSV) |
| debian:linux-4.19 | 4.19.160-2~deb9u1 · Debian:9 | Package registry (OSV) |
| opensuse:kernel-debug | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-default | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-default-base | 5.3.18-lp152.54.1.lp152.8.12.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-docs | 5.3.18-lp152.54.2 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-kvmsmall | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-obs-build | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-obs-qa | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-preempt | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-source | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-syms | 5.3.18-lp152.54.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:kernel-vanilla | 4.12.14-lp151.28.87.2 · openSUSE:Leap 15.1 | Package registry (OSV) |
| suse:kernel-azure | 5.3.18-18.29.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP2 | Package registry (OSV) |
| suse:kernel-default | 4.12.14-122.54.1 · SUSE:Linux Enterprise High Availability Extension 12 SP5 | Package registry (OSV) |
| suse:kernel-docs | 4.12.14-122.54.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5 | Package registry (OSV) |
| suse:kernel-obs-build | 4.12.14-122.54.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5 | Package registry (OSV) |
| suse:kernel-rt | 5.3.18-16.1 · SUSE:Real Time Module 15 SP2 | Package registry (OSV) |
| suse:kernel-rt_debug | 5.3.18-16.1 · SUSE:Real Time Module 15 SP2 | Package registry (OSV) |
| suse:kernel-source | 4.12.14-122.54.1 · SUSE:Linux Enterprise Server 12 SP5 | Package registry (OSV) |
| suse:kernel-source-azure | 5.3.18-18.29.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP2 | Package registry (OSV) |
| suse:kernel-source-rt | 5.3.18-16.1 · SUSE:Real Time Module 15 SP2 | Package registry (OSV) |
| suse:kernel-syms-azure | 5.3.18-18.29.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP2 | Package registry (OSV) |
| suse:kernel-syms-rt | 5.3.18-16.1 · SUSE:Real Time Module 15 SP2 | Package registry (OSV) |
| suse:kgraft-patch-SLE12-SP5_Update_13 | 1-8.3.1 · SUSE:Linux Enterprise Live Patching 12 SP5 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-21-0017 · Jan 8, 2021(Linux Kernel Güvenlik Güncellemesi)
- TR-20-1028 · Dec 9, 2020(Linux Kernel Güvenlik Güncellemesi)
- TR-20-987 · Nov 23, 2020(Linux Kernel Güvenlik Güncellemesi)
Technical details
Attack conditions
- Physical access to the device is required.
- Administrator privileges are required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- low · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Physical
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- Low
- Availability impact
- High
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (5 more)Show less
- cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9.7
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3c4e0dff2095c579b142d5a0693257f1c58b4804
- lists.debian.org/debian-lts-announce/2020/12/msg00015.html
- lists.debian.org/debian-lts-announce/2020/12/msg00027.html
- security.netapp.com/advisory/ntap-20210108-0003/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.