CVE-2026-120456

L-SMASH through 2.14.5 Heap Out-of-Bounds Write via hdlr and url Boxes

MEDIUM
6.1
CVSS Score
Published: November 2, 2026 at 02:29 PM UTC
Updated: November 2, 2026 at 06:18 PM UTC
1 product affected across 1 vendorl-smash

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Severity
MEDIUM6.1
SSVC
No known exploit

Description

L-SMASH through 2.14.5 contains a heap out-of-bounds write vulnerability in isom_read_hdlr() and isom_read_dref_entry() in core/read.c triggered by oversized box sizes. Attackers can supply crafted MP4 or MOV files declaring hdlr or url box sizes larger than remaining data, stalling the stream position and corrupting heap memory to crash applications.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUMVulnCheck
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-787

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