CVE-2020-9391: fedoraproject fedora Out-of-bounds Write
Vulnerability summary
CVE-2020-9391 is a medium (CVSS 5.5) Out-of-bounds Write vulnerability in fedoraproject fedora. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 44% of scored vulnerabilities. 2 public exploits are recorded.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2Timeline
- 25-02-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
An issue was discovered in the Linux kernel 5.4 and 5.5 through 5.5.6 on the AArch64 architecture. It ignores the top byte in the address passed to the brk system call, potentially moving the memory break downwards when the application expects it to move upwards, aka CID-dcde237319e6. This has been observed to cause heap corruption with the GNU C Library malloc implementation.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.52%
Chance of exploitation in the next 30 days
Percentile
44%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.52% on 04-10-2026
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
2 foundExploit Reference (bugzilla.redhat.com)
Maturity: unknown
Exploit Reference (openwall.com)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Netapp7 products
- active_iq_unified_managerna
- cloud_backupna
- data_availability_servicesna
- h410c_firmwarena
- hci_management_nodena
Ubuntu4 products
- linux-azure-edgeAll versions (No fix recorded)
- linux-gcp-edgeAll versions (No fix recorded)
- linux-hwe-edgeAll versions (No fix recorded)
- linux-raspi2All versions (No fix recorded)
Debian1 product
- linux< 5.5.13-1
Fedoraproject1 product
- fedoraEOL31
Linux1 product
- linux_kernelEOL≥ 5.5, ≤ 5.5.6 | 5.4
5 vendors · 14 products
References
9 links- bugzilla.redhat.com/show_bug.cgi?id=1797052X Refsource MISCREPORTExploitIssue TrackingPatchThird Party Advisory
- www.openwall.com/lists/oss-security/2020/02/25/6Mailing ListX Refsource MLISTREPORTExploitThird Party Advisory
