Vulnerability · Published Oct 5, 2026 · Assigned by Docker
CVE-2026-93318Cache poisoning via unvalidated image layer DiffIDs
High 7.5
In plain English
A high-severity security flaw in BuildKit from moby. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities).
Official description
A malicious image can advertise DiffIDs from another image while containing different layer contents. In affected versions, BuildKit could use the advertised DiffIDs to derive cache and snapshot identity without validating that they matched the actual layer contents. If a BuildKit daemon with shared or persistent cache first processes such a malicious image, a later build using the victim image may mount the attacker-controlled layer contents as the base image. This can allow code from the malicious image to run in the victim build, for example by replacing a commonly executed path such as /bin/sh. The attacker-controlled code may read build secrets mounted into the build, access other build resources, alter output artifacts, or hang the build. The issue affects both regular snapshotters and lazy-pulling snapshotters such as stargz.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:26.04:LTS | docker.io | no fix listed | UBUNTU-CVE-2026-93318 |
| Ubuntu:26.10 | docker.io | no fix listed | UBUNTU-CVE-2026-93318 |
| Ubuntu:26.04:LTS | docker.io-app | no fix listed | UBUNTU-CVE-2026-93318 |
| Ubuntu:26.10 | docker.io-app | no fix listed | UBUNTU-CVE-2026-93318 |
Affected products (as reported)
Weakness: CWE-354 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N