A slab-out-of-bounds read in fbcon in the Linux kernel before 5.9.7 could be used by…
Priority LOW 23CWE-125Published · Updated
Key facts
- Attack vector
- Physical
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · High
- Fix status
- Partial Red Hat: 4 fixed, 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
EPSS 0.00517 44th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 2 advisoriesRed Hat: 4 fixed, 4 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
Red Hat 2 advisories
- RHSA-2021:1739 Released 2021-05-18 · Red Hat rating Importantkernel-rt security and bug fix update
- Red Hat Enterprise Linux Real Time (v. 8) kernel-rt-4.18.0-305.rt7.72.el8, kernel-rt-core-4.18.0-305.rt7.72.el8, kernel-rt-debug-4.18.0-305.rt7.72.el8 +7
- Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt-4.18.0-305.rt7.72.el8, kernel-rt-core-4.18.0-305.rt7.72.el8, kernel-rt-debug-4.18.0-305.rt7.72.el8 +9
- RHSA-2021:1578 Released 2021-05-18 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-305.el8
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-305.el8, kernel-4.18.0-305.el8, kernel-abi-stablelists-4.18.0-305.el8 +19
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise MRG 2 | Affected | No fix planned: Will not fix |
| Red Hat CodeReady Linux Builder (v. 8) | Fixed | RHSA-2021:1578 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2021:1578 |
| Red Hat Enterprise Linux Real Time (v. 8) | Fixed | RHSA-2021:1739 |
| Red Hat Enterprise Linux Real Time for NFV (v. 8) | Fixed | RHSA-2021:1739 |
Timeline
- 2026-10-02 Threatist record created from CVE-2020-28974
- 2026-10-03 Alias added: GHSA-vqgg-ch69-x69v
References
Advisory 5
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9.7
- [oss-security] 20201124 Re: Linux kernel slab-out-of-bounds Read in fbcon
- [debian-lts-announce] 20201210 [SECURITY] [DLA 2483-1] linux-4.19 security update
- [debian-lts-announce] 20201218 [SECURITY] [DLA 2494-1] linux security update
- https://security.netapp.com/advisory/ntap-20210108-0003/
Sources
- CVE-2020-28974 · CVE Program
- CVE-2020-28974 · NVD
- FIRST EPSS
- GHSA-vqgg-ch69-x69v · GitHub Advisory Database · CC BY 4.0
- CVE-2020-28974 · Red Hat security data · CC BY 4.0
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