Vulnerability in Stoatchat
CVE-2026-100676
January, the media proxy/embed service of stoatchat (stoatchat/stoatchat), before version 0.15.5 improperly resolves SVG <image href> values as local filesystem paths when a fetched resource is served as image/svg+xml. An unauthenticated remote attacker who causes the service to proxy an attacker-hosted SVG (e.g. via the /proxy endpoint) can determine whether local files exist through observable response-time differences, and can cause supported local image files to be disclosed after re-encoding. Because each referenced file is read in full with no effective limit on the number or total volume of reads, a single request can also generate an unbounded amount of local filesystem I/O and memory pressure (the published proof of concept drives about 4.34 GB of reads), leading to denial of service. The issue is fixed in 0.15.5.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (43.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-qv38-hwhv-jm49) (vendor-advisory)
- VulnCheck Advisory: stoatchat before 0.15.5 Local Filesystem Read via SVG (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100676?
- CVE-2026-100676 is a high-severity vulnerability in Stoatchat, classified under Protection Mechanism Failure. CVSS score: 8.2/10. Published 2026-09-26.
- How severe is CVE-2026-100676?
- High severity. CVSS v3 base score is 8.2 out of 10.