Medium

CVE-2026-118593 — Kernel: local_bh imbalance in seg6_input_core() drop path (incomplete fix for cve-2026-46099)

A flaw was found in Red Hat Enterprise Linux 9 kernel builds. An incomplete backport of the CVE-2026-46099 fix in RHEL 9.6 through 9.10 left a local_bh imbalance in seg6_input_core(), where the drop path returns with bottom halves still disabled. This can lead to softirq starvation and denial of service on systems with SRv6 tunnels configured. Upstream and RHEL 10 are not affected.

Published Oct 30, 2026 · Updated Oct 30, 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

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

—

No EPSS score.

Affects

Red Hat

Red Hat Enterprise Linux 9 and 2 more

CVSS base

5.9

Medium · 2 source(s)

Remediation

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

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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 (Red Hat Red Hat Enterprise Linux 9, Red Hat Red Hat OpenShift Container Platform 4, Red Hat Red Hat OpenShift Container Platform 5).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Red Hat	Red Hat Enterprise Linux 9	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat OpenShift Container Platform 4	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat OpenShift Container Platform 5	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

Network

Attack complexity

High

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

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
5.9	CVSS 3.1	Medium	2.2	3.6	secalert@redhat.com via NIST National Vulnerability Database
5.9	CVSS 3.1	Medium	—	—	redhat via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-667

Other CVEs with this weakness →

Detection

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

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · red hat/red hat enterprise linux 9, red hat/red hat openshift container platform 4, red hat/red hat openshift container
Oct 30, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 30, 2026
CVSS changed · 5.9
Oct 30, 2026 · NIST National Vulnerability Database
Source status changed · → Awaiting Analysis
Oct 30, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 30, 2026 · Alertas do Telegram
CVE published
Oct 30, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 30, 2026 – Oct 30, 2026
1× Official description updated · Oct 30, 2026 – Oct 30, 2026

References

2 on the record

access.redhat.com/security/cve/CVE-2026-118593
vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database
bugzilla.redhat.com/show_bug.cgi
issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Red Hat
every CVE for this vendor

CWE-667
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-119528 Gimp: gimp: stack buffer overflow in psd image resource header loader 37m
Low CVE-2026-115456 Gcc: out-of-bounds read in std::from_chars 5h
Medium CVE-2026-114691 Gcc: integer wrap in `std 6h
Medium CVE-2026-114690 Gcc: confirmed out-of-bounds read/write in libstdc++ parallel `std 6h
High CVE-2026-103963 Glib-networking: unbounded tls 1.3 session ticket queue growth in glib-networking allows remote denial of service 9h
Low CVE-2026-118475 Eog: eye of gnome: buffer overrun when parsing malicious png files with non-standard iccp chunk 12h

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 FIRST EPSS score.
No fixed version, patch or mitigation documented.
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-2026-118593 is "Kernel: local_bh imbalance in seg6_input_core() drop path (incomplete fix for cve-2026-46099)", rated Medium. It affects Red Hat Enterprise Linux 9 (Red Hat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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