L-SMASH through 2.14.5 contains a heap out-of-bounds write vulnerability in isom_read_hdlr() and
Source GCVE Database
Not known to be exploited · CVSS 6.9 Medium.
Data as of 2 Nov 2026, 16:44 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.9 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 6.1 |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 2 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| L-SMASHL-SMASH | Affected
| Fixed in– |
GitHubL-SMASHpkg:github/L-SMASHOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, avoid processing untrusted or malformed MP4 or MOV files with vulnerable L-SMASH versions.
Description
L-SMASH versions through 2.14.5 have a heap out-of-bounds write vulnerability in the isom_read_hdlr() and isom_read_dref_entry() functions. This flaw is triggered by crafted MP4 or MOV files that declare handler (hdlr) or URL box sizes larger than the actual remaining data, causing heap corruption and application crashes.
References
- nvd.nist.gov/vuln/detail/CVE-2026-120456 (opens in a new tab)
- github.com/l-smash/l-smash/issues/112 (opens in a new tab)
- github.com/l-smash/l-smash/commit/805ee3c9632e054198d3cb5b09c7b7aa36cdd791 (opens in a new tab)
- github.com/l-smash/l-smash/blob/v2.14.5/core/read.c (opens in a new tab)
- github.com/l-smash/l-smash/blob/v2.14.5/core/read.c (opens in a new tab)
- hackmd.io/@haindpwn/lsmash-hdlr-dref-box-size-oob-write (opens in a new tab)
- vulncheck.com/advisories/l-smash-through-2.14.5-heap-out-of-bounds-write-via-hdlr-and-url-boxes (opens in a new tab)