CVE-2026-125257: FFmpeg through 9.0.2 Heap Overflow via Nellymoser Encoder Trellis Search
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- 0.1%
EPSS score, percentile 3.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 7.3 High
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
- Which versions are affected?
Affected
- 9.0.2 and earlier
Source: CISA KEV 2026.11.10, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
Description
FFmpeg through 9.0.2 Heap Overflow via Nellymoser Encoder Trellis Search
FFmpeg through 9.0.2 contains an off-by-one heap overflow vulnerability in get_exponent_dynamic() in libavcodec/nellymoserenc.c that allows writing one element past the opt and path allocations. Attackers can supply crafted audio to applications encoding Nellymoser with trellis enabled, causing idx to equal OPT_SIZE and overwrite adjacent heap memory.
Source: CVE List, as of . About the data.
What to do
Advisories and patches
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
Versions by product, as listed in the CVE record (1 product)
| Status | Versions |
|---|---|
| Affected | 9.0.2 and earlier |
Versions not listed are: unaffected.
Source: CVE List, as of . About the data.
Weakness
CWE-193
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published |