CVE-2026-95838

Impact

A vulnerability exists in containerd's layer unpack handler where the processing of certain image layers causes superlinear time complexity. During the unpack operation, specific file configurations within the layer can trigger repeated directory traversals.

Consequently, pulling or importing a maliciously crafted image can result in increased unpack times and a moderate increase in CPU usage. This delays container startup, even if the compressed image layers are small. Additionally, in orchestrators like Kubernetes that apply concurrency limits to image pulls, these excessively long operations can reduce the available concurrency for other pulls, potentially delaying unrelated container deployments.

Patches

This bug has been fixed in containerd 2.3.5, 2.2.8, 2.0.12, and 1.7.35. Users should update to these versions to resolve the issue.

Workarounds

There are no known workarounds for this issue. Users are advised to only pull and import trusted images from known registries until the patch can be applied.

Credits

The containerd project would like to thank Jakub Ciolek of AlphaSense for responsibly disclosing this issue in accordance with the containerd security policy.

For more information

If you have any questions or comments about this advisory:

• Open an issue in containerd
• Email us at [email protected]

To report a security issue in containerd:

• Report a new vulnerability
• Email us at [email protected]

containerd is an industry-standard container runtime with an emphasis on simplicity, robustness and portability. It is available as a daemon for Linux and Windows, which can manage the complete container lifecycle of its host system: image transfer and storage, container execution and supervision, low-level storage and network attachments, etc.

Security Fix(es):

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.(CVE-2026-95838)

containerd is an industry-standard container runtime with an emphasis on simplicity, robustness and portability. It is available as a daemon for Linux and Windows, which can manage the complete container lifecycle of its host system: image transfer and storage, container execution and supervision, low-level storage and network attachments, etc.

Security Fix(es):

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.(CVE-2026-95838)

containerd is an industry-standard container runtime with an emphasis on simplicity, robustness and portability. It is available as a daemon for Linux and Windows, which can manage the complete container lifecycle of its host system: image transfer and storage, container execution and supervision, low-level storage and network attachments, etc.

Security Fix(es):

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.(CVE-2026-95838)

containerd is an industry-standard container runtime with an emphasis on simplicity, robustness and portability. It is available as a daemon for Linux and Windows, which can manage the complete container lifecycle of its host system: image transfer and storage, container execution and supervision, low-level storage and network attachments, etc.

Security Fix(es):

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.(CVE-2026-95838)

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd is an open-source container runtime. Prior to 1.7.35, 2.0.12, 2.2.8, and 2.3.5, containerd's layer unpack handler repeatedly traverses directories for certain opaque whiteout configurations. A malicious image layer can trigger repeated directory traversals while opaque whiteouts are processed. Pulling or importing the image can consume CPU, delay container startup, and reduce image-pull concurrency for unrelated deployments. This issue is fixed in versions 1.7.35, 2.0.12, 2.2.8, and 2.3.5.

containerd: Unpack DoS via repeated opaque whiteouts in github.com/containerd/containerd

These are all security issues fixed in the google-osconfig-agent-20261015.00-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the kubectl-retina-1.3.1-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the containerd-2.4.2-1.1 package on the GA media of openSUSE Tumbleweed.

This update for google-osconfig-agent fixes the following issues:

• CVE-2026-61801: github.com/moby/sys/user: unbounded parsing of user and group database files can lead to denial of service (bsc#1284870).
• CVE-2026-78669: golang.org/x/net/http2: excessive CPU consumption from repeated initial window changes (bsc#1285283).
• CVE-2026-95838: github.com/containerd/containerd: processing of certain image layers causes superlinear time complexity in unpack handler and can lead to DoS (bsc#1285135).

Changes for google-osconfig-agent:

• Update to version 20261015.00

• Add scalibr os benchmarks (#1044)

This update for containerd fixes the following issues:

• CVE-2026-39882: go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp: Memory exhaustion via uncapped HTTP response body reading (bsc#1274214).
• CVE-2026-47262: Denial of Service (DoS) condition via a maliciously crafted image (bsc#1268441).
• CVE-2026-53488: CRI plugin propagates labels from an image config to a container without validation (bsc#1268430).
• CVE-2026-53493: a crafted OCI index graph can force very high CPU/memory usage during PullImage (before container start), causing long ContainerCreating stalls and, at larger sizes, node/runtime instability (bsc#1282669).
• CVE-2026-53495: CRI ExecSync Goroutine Leak Leads to Node-Level Denial of Service (bsc#1280007).
• CVE-2026-95838: github.com/containerd/containerd: processing of certain image layers causes superlinear time complexity in unpack handler and can lead to DoS (bsc#1285124).

This update for containerd fixes the following issues:

• CVE-2026-39882: go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp: Memory exhaustion via uncapped HTTP response body reading (bsc#1274214).
• CVE-2026-47262: Denial of Service (DoS) condition via a maliciously crafted image (bsc#1268441).
• CVE-2026-53493: a crafted OCI index graph can force very high CPU/memory usage during PullImage (before container start), causing long ContainerCreating stalls and, at larger sizes, node/runtime instability (bsc#1282669).
• CVE-2026-53495: CRI ExecSync Goroutine Leak Leads to Node-Level Denial of Service (bsc#1280007).
• CVE-2026-95838: github.com/containerd/containerd: processing of certain image layers causes superlinear time complexity in unpack handler and can lead to DoS (bsc#1285124).