Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV N H P N N H H H 9.2 .0048 39.8 —
AFFECTED Product Versions Fixed Squash unspecified —
TIMELINE Oct 12 Reserved by VulnCheck Oct 12 Published (CNA: VulnCheck) Oct 13 EXPLOIT PUBLISHED — CVE-2026-109391 (Square Squash). Public exploit reference added.
Square Squash through commit e73f280 contains an insecure deserialization vulnerability that allows unauthenticated attackers to store crafted YAML via the POST /api/1.0/symbolication endpoint. When occurrences referencing the attacker-controlled symbolication UUID are symbolicated, the stored values are passed to YAML.load with SafeYAML in unsafe mode, enabling arbitrary Ruby object deserialization and potential code execution.
| Date | Event | Detail |
|---|---|---|
| October 12, 2026 | Reserved | Reserved by VulnCheck |
| October 12, 2026 | Published | Published (CNA: VulnCheck) |
| October 13, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-109391 (Square Squash). Public exploit reference added. |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| Square | Squash | — | — | — |
Authoritative record: CVE-2026-109391 at cve.org
Vendors: square
Weaknesses: CWE-502
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-109391 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
