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CVE-2026-93318

Cache poisoning via unvalidated image layer DiffIDs

High7.5EPSS 0.17%
Published
Updated
Reserved
Assigned by
Docker

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.

Scores

CVSS scores of CVE-2026-93318, by who scored it
Scored byCVSSScoreVector
DockerCNA (assigner)4.0High7.5CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
NVDNVD · Awaiting Analysis4.0High7.5CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS (exploitation in 30 days)
0.17% · top 94% of all CVEs (7 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: total
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The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

Affected products

What to do

Workaround: Do not share BuildKit daemon cache between trusted and untrusted builds. Use isolated BuildKit daemons or ephemeral builders for untrusted image sources, or prune BuildKit cache after processing untrusted images. Disabling stargz alone is not sufficient because regular snapshotters are also affected.

References (2)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .