CVE Intelligence
High

CVE-2026-98454 — smb: client: fix create context out-of-bounds reads

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix create context out-of-bounds reads smb2_parse_contexts() validates the complete create-context area but does not limit each record to its Next field before dispatching it. A malformed chain can therefore expose bytes beyond the current context to a handler. The QFid handler also used a full response-structure cast although it only reads DiskFileId. The SMB2/SMB3 lease parsers made the same layout assumption: they read LeaseState and LeaseFlags at canonical offsets rather than at DataOffset. A valid non-canonical DataOffset could therefore yield unrelated in-bounds data, while a short DataLength was still accepted. Limit each context to its Next value, reject offsets before the context header, and reject malformed chains. Bound the name range by the current context and do not dispatch a known handler when DataLength is zero. Read the QFid DiskFileId only when the context data covers that field. Parse the lease context from DataOffset and require DataLength to match the v1 or v2 lease_context size used by ksmbd. A size mismatch skips lease parsing without failing the open.

Published Oct 18, 2026 · Updated Oct 30, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

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 0.3% (30-day exploitation probability)+4
  • Technical severity (high)+6

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
0.34%
ahead of 28% of scored CVEs · Oct 30, 2026
Affects
Linux
Linux
CVSS base
8.1
High · 3 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.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < e4c49012708c917eafd9c27054b02d0f8b30fe64≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < 28bc9a871799363afa3139e961a8e3684feb8704≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < 05a7fd80024ff32b9b40ab1478bb172eeab1c386≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < cecc5399987e73a528ce2b662eeb54af69163cbd≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < 67f4c1c6a1b51e203d986779299824d1c2c590a6version 3.7≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < 34245048d6c1fa6d7be4f0dec1d14b5be02360e1≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < 0a8c2a6715c2a67b7abbbf874fccc9f5518146d9
and 1 more ≥ b8c32dbb0deb287a5fcb78251e4eae6c7275760d and < 43d0ca48bb902d554b6531862248810d2ae3b8ef
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
Low
Privileges required
None
User interaction
Required
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.

ScoreVersionSeverityExpl.ImpactScored by
8.1 CVSS 3.1 High 2.8 5.2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
8.1 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
8.1 CVSS 3.1 High — — Linux via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

EPSS over time FIRST

Oct 19, 2026 → Oct 30, 2026 · 12 reading(s) · max 0.34%

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 · linux/linux
    Oct 30, 2026 · CVE Program (cve.org) e CISA ADP
  • CVSS changed · 8.1
    Oct 24, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 18, 2026
  • Affected products added · linux/linux
    Oct 18, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 18, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 18, 2026 · Alertas do Telegram
  • CVE published
    Oct 18, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 3× References added · Oct 18, 2026 – Oct 30, 2026
  • 1× Official description updated · Oct 18, 2026 – Oct 18, 2026

References

10 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 3d
  • CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 3d
  • CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 3d
  • CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 3d
  • CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 3d
  • CVE-2026-99210 accel/rocket: clear rdev on device init failure 3d

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 fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • 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-2026-98454 is "smb: client: fix create context out-of-bounds reads", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.1 describes technical severity. EPSS 0.34% 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.

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