Medium Memory corruption

CVE-2023-39189 — Kernel: netfilter: nftables out-of-bounds read in nf_osf_match_one()

A flaw was found in the Netfilter subsystem in the Linux kernel. The nfnl_osf_add_callback function did not validate the user mode controlled opt_num field. This flaw allows a local privileged (CAP_NET_ADMIN) attacker to trigger an out-of-bounds read, leading to a crash or information disclosure.

Published Oct 9, 2023 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: redhat

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+5
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.4%

ahead of 33% of scored CVEs · Oct 14, 2026

Affects

Fedoraproject

Fedora and 4 more

CVSS base

6.0

Medium · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — bugzilla.redhat.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Fedoraproject Fedora, Linux Linux Kernel, Red Hat Enterprise Linux…).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Fedoraproject	Fedora	version 38	Vulnerable	NIST National Vulnerability Database
Linux	Linux Kernel	< 6.6	Vulnerable	NIST National Vulnerability Database
Red Hat	Enterprise Linux	version 8.0version 9.0	Vulnerable	NIST National Vulnerability Database
Red Hat	Red Hat Enterprise Linux 8	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 9	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

High

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
6.0	CVSS 3.1	Medium	0.8	5.2	nvd@nist.gov via NIST National Vulnerability Database
5.1	CVSS 3.1	Medium	0.8	4.2	secalert@redhat.com via NIST National Vulnerability Database
5.1	CVSS 3.1	Medium	—	—	redhat via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H (score shown at the top: nvd@nist.gov)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 6.0 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-125 · Out-of-bounds Read

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · red hat/red hat enterprise linux 8, red hat/red hat enterprise linux 9
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 14, 2026
Fix documented
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 6.0
Oct 14, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 14, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 14, 2026 · NIST National Vulnerability Database
2023
CVE published
Oct 9, 2023 · redhat

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

8 on the record

bugzilla.redhat.com/show_bug.cgi
Issue Tracking, Patch, Third Party Advisory, issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/security/cve/CVE-2023-39189
Third Party Advisory, vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-398330.html
NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2024:3138
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
lists.debian.org/debian-lts-announce/2024/01/msg00004.html
NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2024:2394
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-794697.html
NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2024:2950
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Fedoraproject
every CVE for this vendor

Memory corruption
same class

CWE-125
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-110927 Openssh: openssh: a compressed payload can expand past the maximum packet size 7h
Medium CVE-2026-110924 Openssh: openssh: gssapi delegated credentials can be stored after a failed authentication 7h
Medium CVE-2026-110926 Openssh: openssh: shared lz77 compression dictionary leaks plaintext across channels 15h
Medium CVE-2026-110925 Openssh: openssh: '$' and '\' in a command-line username expand through %u 15h
Medium CVE-2026-110923 Openssh: openssh: sftp can write outside the destination directory from a server-supplied path 15h
High CVE-2026-86848 Dpdk: dpdk: time-of-check/time-of-use vulnerability allowing guest-triggered out-of-bounds write in vhost-crypto 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-39189 is "Kernel: netfilter: nftables out-of-bounds read in nf_osf_match_one()", rated Medium. It affects Fedora (Fedoraproject); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.0 describes technical severity. EPSS 0.40% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.