Vulnerability DatabaseCVE-2026-120456
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CVE-2026-120456
Published:November 02, 2026
Updated:November 04, 2026
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.
Related Resources (9)
https://hackmd.io/@haindpwn/lsmash-hdlr-dref-box-size-oob-write
https://github.com/l-smash/l-smash/issues/112
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120456.json
https://github.com/l-smash/l-smash/blob/v2.14.5/core/read.c#L853-L876
https://github.com/l-smash/l-smash
https://github.com/l-smash/l-smash/blob/v2.14.5/core/read.c#L688-L717
https://github.com/l-smash/l-smash/commit/805ee3c9632e054198d3cb5b09c7b7aa36cdd791
https://www.vulncheck.com/advisories/l-smash-through-2.14.5-heap-out-of-bounds-write-via-hdlr-and-url-boxes
https://nvd.nist.gov/vuln/detail/CVE-2026-120456
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CVSS v4
Base Score:
6.9
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.1
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
HIGH
Weakness Type (CWE)
Out-of-bounds Write
CWE-787
EPSS
Base Score:
0.16