CVE-2026-75904 — libmodplug <= 0.8.9.1 - Out-of-Bounds Read in pat_smplooped via Crafted MIDI File
libmodplug through 0.8.9.1 contains an out-of-bounds read in pat_smplooped in src/load_pat.cpp. The function validates only the upper bound of its sample index against MAXSMP and then subtracts one before indexing the 191-byte static array pat_loops, so an index of zero reads pat_loops[-1], one byte before the array. The index is the smpno field of a parsed MIDI event, which is initialised to zero and only later overwritten from a program-change parameter, so an event reaching the note test before an instrument is assigned carries zero. A 32-byte MIDI file supplied to the library's public ModPlug_Load entry point drives the path through CSoundFile::Create, CSoundFile::ReadMID, and MID_ReadPatterns to the read. The byte read out of bounds determines whether a note event is treated as looping, so adjacent static storage influences playback state.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- CISA SSVC: exploitation "poc"+5
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Konstanty Bialkowski Libmodplug).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Konstanty Bialkowski | Libmodplug | ≤ 0.8.9.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 4.8 | CVSS 4.0 | Medium | — | — | disclosure@vulncheck.com via NIST National Vulnerability Database |
| 4.8 | CVSS 4.0 | Medium | — | — | VulnCheck via CVE Program (cve.org) e CISA ADP |
| 3.3 | CVSS 3.1 | Low | 1.8 | 1.4 | disclosure@vulncheck.com via NIST National Vulnerability Database |
| 3.3 | CVSS 3.1 | Low | — | — | VulnCheck via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N (score shown at the top: disclosure@vulncheck.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · konstanty bialkowski/libmodplug
- SSVC assessment updated
- Record published
- CVSS changed · 3.3
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
5 on the record
- github.com/Konstanty/libmodplug/blob/d1b97ed0020bc620a059d3675d1854b40bd2608d/sr
- github.com/Konstanty/libmodplug/blob/d1b97ed0020bc620a059d3675d1854b40bd2608d/sr
- github.com/Konstanty/libmodplug/issues/103
- www.vulncheck.com/advisories/libmodplug-out-of-bounds-read-in-pat-smplooped-via-crafted
- github.com/Konstanty/libmodplug
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-111271 libmodplug through 0.8.9.1 Heap Out-of-Bounds Read via CSoundFile::ReadAMS2 2h
- Medium CVE-2026-111270 libmodplug through 0.8.9.1 Heap Out-of-Bounds Write via CSoundFile::ReadDSM 2h
- Medium CVE-2026-108577 Konstanty Bialkowski libmodplug ABC Music Format load_abc.cpp abc_add_gchord resource consumption 4d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-75904 is "libmodplug <= 0.8.9.1 - Out-of-Bounds Read in pat_smplooped via Crafted MIDI File", rated Low. It affects Libmodplug (Konstanty Bialkowski); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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