---
title: "CVE-2026-21089: libsubextractor.so - Buffer Overflow"
description: "libsubextractor.so prior to SMR Sep-2026 Release 1 contains a buffer overflow caused by improper input validation in removing style tag, letting local attackers write out-of-bounds memory, exploit requires local access."
url: https://panop.io/threat-heartbeat/CVE-2026-21089/
---

# CVE-2026-21089 libsubextractor.so - Buffer Overflow

libsubextractor.so prior to SMR Sep-2026 Release 1 contains a buffer overflow caused by improper input validation in removing style tag, letting local attackers write out-of-bounds memory, exploit requires local access.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.10% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-21089)

## Details

Type

Buffer Overflow

Impact

Remote Code Execution

CVSS vector

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

Published

9 September 2026

Updated

15 October 2026

Weakness

[CWE-20](https://cwe.mitre.org/data/definitions/20.html)

## Vendor fix

Update to SMR Sep-2026 Release 1 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-2026-21089](https://nvd.nist.gov/vuln/detail/CVE-2026-21089)
- [https://security.samsungmobile.com/securityUpdate.smsb?year=2026&month=09](https://security.samsungmobile.com/securityUpdate.smsb?year=2026&month=09)

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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

Panop answers these inside your environment, for this CVE and every other finding.

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