L-SMASH through 2.14.5 Heap Out-of-Bounds Write via hdlr and url Boxes
- Exploited
- No known exploitation
- Fix
- Fix or patch referenced
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects l-smash v2.14.5 and master HEAD, where the same code is present Victim or attacker opens a crafted .mp4 or .mov file through lsmash_read_file A box declares a size larger than the bytes actually present for that box
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 12/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fix or patch referenced
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
What to do
Check whether your setup matches what the bug needs.
Affects l-smash v2.14.5 and master HEAD, where the same code is present Victim or attacker opens a crafted .mp4 or .mov file through lsmash_read_file A box declares a size larger than the bytes actually present for that boxApply the patch listed under Evidence.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- L-SMASH L-SMASH
through 2.14.5
Evidence 6
- Patch
- Report
- Repository
- Repository
- Link
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-120456
What does this mean?
A crafted MP4 or MOV file can make L-SMASH write data past the end of a heap buffer while parsing its hdlr and url boxes. The write length comes from attacker-influenced values, which can corrupt heap memory and crash the application.Source: github.com
Am I affected, and how do I check?
The advisory tested L-SMASH v2.14.5, the latest release, and says the same code is present in master HEAD; all versions through 2.14.5 are listed as affected. The bug is reached when a .mp4 or .mov file is opened through lsmash_read_file, and it needs a box whose declared size is larger than the bytes actually present. To check a build, look at the version it reports or the release tag you compiled from.Source: github.com
What should I do about it?
No fixed version is listed in the facts, so there is no confirmed upgrade target yet. Avoid opening untrusted .mp4 or .mov files with L-SMASH until a patched release is available and you have checked the vendor's advisory.Source: github.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data