# CVE-2026-121803: CVE-2026-121803

- Exploited (CISA KEV): no
- Published: 2026-11-04
- CVSS: not scored
- EPSS: no score

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | No public claim | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | No public claim | — | — |
| Vercel | No public claim | — | — |
| F5 | No public claim | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

## Social

3 posts seen since 2026-11-04.

- bluesky 2026-11-04: CVE-2026-121803 - Out-of-bounds Write in UFS Firmware CVE ID : CVE-2026-121803    Published : Nov. 4, 2026, 4:17 a.m. \| 47 minutes ago    Description : In UFS Field Firmware Update (FFU) functionality, there is a possible out-of-bounds write due to missing bounds checking on t... (https://bsky.app/profile/cve.skyfleet.blue/post/6eaupuia26lhd)
- x 2026-11-04: 🚨 CVE-2026-121803 (9.3) 🚨  Unisoc's UFS firmware update code lets any app on the device run code or crash the device with a malformed update.  UFS is a flash storage standard, and Field Firmware Update is how its firmware gets replaced. No fixed version is named. https://t.co/… (https://x.com/ParameterWatch/status/2117845744510193802)
- bluesky 2026-11-04: CVE-2026-121803 The update feature used for UFS storage devices can write data beyond its intended area because it does not check the size of a data table. This can cause the system to stop working or allow unauthorized code…  Too many irrelevant or confusing CVEs? Use stackflag… (https://bsky.app/profile/stackflag.bsky.social/post/3mzhjwknkpq22)

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2026-121803 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-121803