CVE Intelligence
High Memory corruption exploit reference

CVE-2026-115505 — libsmb2 before 6.3 Integer Overflow in DCE/RPC NDR Decoder via NetrShareEnum

libsmb2 before 6.3 contains integer overflow vulnerabilities in the DCE/RPC NDR decoder in lib/dcerpc.c that allow heap out-of-bounds reads and writes. A malicious SMB server or machine-in-the-middle on unsigned connections can send crafted NetrShareEnum replies with wrapping actual_count or max_count values when clients call smb2_share_enum_async(), corrupting heap memory.

Published Oct 22, 2026 · Updated Oct 23, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: VulnCheck

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 0.2% (30-day exploitation probability)+2
  • 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
0.21%
ahead of 11% of scored CVEs · Oct 28, 2026
Affects
Sahlberg
Libsmb2
CVSS base
7.6
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 (Sahlberg Libsmb2).
  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 matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Sahlberg Libsmb2 < 6.3 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
Low
Integrity
Low
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
7.2 CVSS 4.0 High — — disclosure@vulncheck.com via NIST National Vulnerability Database
7.2 CVSS 4.0 High — — VulnCheck via CVE Program (cve.org) e CISA ADP
7.6 CVSS 3.1 High 2.8 4.7 disclosure@vulncheck.com via NIST National Vulnerability Database
7.6 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.6 CVSS 3.1 High — — VulnCheck via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H (score shown at the top: disclosure@vulncheck.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-190 · Integer Overflow or Wraparound

Other CVEs with this weakness →

EPSS over time FIRST

Oct 23, 2026 → Oct 28, 2026 · 6 reading(s) · max 0.21%

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).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Received → Deferred
    Oct 23, 2026 · NIST National Vulnerability Database
  • Affected products added · sahlberg/libsmb2
    Oct 22, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 22, 2026
  • CVSS changed · 7.6
    Oct 22, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 22, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 22, 2026 · Alertas do Telegram
  • CVE published
    Oct 22, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 22, 2026 – Oct 23, 2026
  • 1× Official description updated · Oct 22, 2026 – Oct 22, 2026

References

8 on the record

Elsewhere on this site

Sahlberg
every CVE for this vendor
Memory corruption
same class
CWE-190
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-110713 libsmb2 through 6.2 Heap Out-of-Bounds Read via File System Info Decoders 14d
  • CVE-2026-110714 libsmb2 through 6.2 Heap Out-of-Bounds Read via decode_acl Integer Underflow 14d
  • CVE-2026-110712 libsmb2 through 6.2 Heap Out-of-Bounds Read via smb2_decode_file_all_info 14d

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 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-2026-115505 is "libsmb2 before 6.3 Integer Overflow in DCE/RPC NDR Decoder via NetrShareEnum", rated High. It affects Libsmb2 (Sahlberg); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.6 describes technical severity. EPSS 0.21% 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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