---
title: "CVE-2026-115505: libsmb2 - Integer Overflow"
description: "libsmb2 < 6.3 contains an integer overflow caused by improper handling of wrapping actual_count or max_count values in DCE/RPC NDR decoder, letting malicious SMB servers or MITM corrupt heap memory, exploit requires unsigned SMB connections."
url: https://panop.io/threat-heartbeat/CVE-2026-115505/
---

# CVE-2026-115505 libsmb2 - Integer Overflow

libsmb2 < 6.3 contains an integer overflow caused by improper handling of wrapping actual\_count or max\_count values in DCE/RPC NDR decoder, letting malicious SMB servers or MITM corrupt heap memory, exploit requires unsigned SMB connections.

CVSS base score 7.6 /10

High

CISA KEV

Not listed

Public exploit

None known

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-115505)

## Details

Type

Integer Overflow

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Published

22 October 2026

Updated

23 October 2026

Weakness

[CWE-190](https://cwe.mitre.org/data/definitions/190.html)

## Vendor fix

Update to version 6.3 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-115505](https://nvd.nist.gov/vuln/detail/CVE-2026-115505)
- [https://github.com/sahlberg/libsmb2/issues/496](https://github.com/sahlberg/libsmb2/issues/496)
- [https://github.com/sahlberg/libsmb2/releases/tag/libsmb2-6.3](https://github.com/sahlberg/libsmb2/releases/tag/libsmb2-6.3)
- [https://hackmd.io/@haindpwn/libsmb2-dcerpc-ndr-count-overflow-oob](https://hackmd.io/@haindpwn/libsmb2-dcerpc-ndr-count-overflow-oob)
- [https://www.vulncheck.com/advisories/libsmb2-before-6.3-integer-overflow-in-dce-rpc-ndr-decoder-via-netrshareenum](https://www.vulncheck.com/advisories/libsmb2-before-6.3-integer-overflow-in-dce-rpc-ndr-decoder-via-netrshareenum)
- [https://github.com/sahlberg/libsmb2](https://github.com/sahlberg/libsmb2)
- [https://github.com/sahlberg/libsmb2/commit/a79f6914cb5ed3f74293d15cdea901261ce179ff](https://github.com/sahlberg/libsmb2/commit/a79f6914cb5ed3f74293d15cdea901261ce179ff)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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