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Linux CVE-2026-98621

| EUVDEUVD-2026-103666
2026-10-18 Linux GHSA-2cjw-phmm-3745
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Monitor Track and reassess. Why: No CVSS yet + weak signal (CWE or non-zero EPSS).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisCVE.org

In the Linux kernel, the following vulnerability has been resolved:

net: gue: reject invalid REMCSUM offsets

The REMCSUM option carries an absolute checksum start and checksum field offset. gue_remcsum() passes them to skb_remcsum_process(), whose partial path stores offset - start in the u16 skb->csum_offset variable. If offset is less than start, this underflows.

A forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM driver which trusts the metadata, leading skb_copy_and_csum_dev() to write two bytes about 64 KiB beyond the destination buffer.

Reject reversed tuples in validate_gue_flags(), after the existing length validation, so all GUE parsers enforce the ordering in one place.

Affected VersionsENISA

Linux fe881ef11cf0220f118816181930494d484c4883 <4b9bc21b2396c396d88dd909caaf73d5be6ff593
Linux patch: 6.1.189
Linux patch: 5.10.271
Linux patch: 5.15.222
Linux fe881ef11cf0220f118816181930494d484c4883 <1eeec0c51fd5598da44080ed96bbd9880021c28b
Linux patch: 7.3-rc5
Linux patch: 6.6.158
Linux fe881ef11cf0220f118816181930494d484c4883 <c20f755338ca234e523dfc943719f194dfc1f903
Linux patch: 0
Linux fe881ef11cf0220f118816181930494d484c4883 <40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f
Linux patch: 7.2.9
Linux fe881ef11cf0220f118816181930494d484c4883 <2566866fc30965d915d0b52b5c3323b362619f0e
Linux fe881ef11cf0220f118816181930494d484c4883 <1d664be4ca49d1696e85239236f4988dfc4653c3
Linux patch: 6.12.112
Linux fe881ef11cf0220f118816181930494d484c4883 <43efb1f997e976f386aa89716f55870cd2cff9ad
Linux patch: 6.18.55
Linux fe881ef11cf0220f118816181930494d484c4883 <97f907203321eee2cc9132d5c9eb47698fb41d35
Linux 4.0

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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Lifecycle Timeline

2
Patch available
Oct 18, 2026 - 16:02 EUVD
CVE Published
Oct 18, 2026 - 15:19 cve.org
UNKNOWN (no severity yet)

Threat Intelligence Overview

EPSS Score
0.2%
Top 89% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity Not scored yet
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
No CVSS yet + weak signal (CWE or non-zero EPSS)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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