Singluarity ineffectively applies of selinux / apparmor LSM process labels

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

SingularityCE and SingularityPRO are open source container platforms. Prior to SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5, if a user relies on LSM restrictions to prevent malicious operations then, under certain circumstances, an attacker can redirect the LSM label write operation so that it is ineffective. The attacker must cause the user to run a malicious container image that redirects the mount of /proc to the destination of a shared mount, either known to be configured on the target system, or that will be specified by the user when running the container. The attacker must also control the content of the shared mount, for example through another malicious container which also binds it, or as a user with relevant permissions on the host system it is bound from. This vulnerability is fixed in SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5.

Source published

2 Dec 2025 17:25:55 UTC

Source modified

2 Dec 2025 17:54:44 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 4.5 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

SingularityCE and SingularityPRO are open source container platforms. Prior to SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5, if a user relies on LSM restrictions to prevent malicious operations then, under certain circumstances, an attacker can redirect the LSM label write operation so that it is ineffective. The attacker must cause the user to run a malicious container image that redirects the mount of /proc to the destination of a shared mount, either known to be configured on the target system, or that will be specified by the user when running the container. The attacker must also control the content of the shared mount, for example through another malicious container which also binds it, or as a user with relevant permissions on the host system it is bound from. This vulnerability is fixed in SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5.

Source published

Dec 2, 2025, 5:25:55 PM (timezone not stated)

Source modified

Dec 2, 2025, 5:54:44 PM (timezone not stated)

Observed here

9 Nov 2026 04:07:39 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 4.5 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

SingularityCE and SingularityPRO are open source container platforms. Prior to SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5, if a user relies on LSM restrictions to prevent malicious operations then, under certain circumstances, an attacker can redirect the LSM label write operation so that it is ineffective. The attacker must cause the user to run a malicious container image that redirects the mount of /proc to the destination of a shared mount, either known to be configured on the target system, or that will be specified by the user when running the container. The attacker must also control the content of the shared mount, for example through another malicious container which also binds it, or as a user with relevant permissions on the host system it is bound from. This vulnerability is fixed in SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5.

Source published

2 Dec 2025 18:15:48 UTC

Source modified

18 Oct 2026 18:10:00 UTC

Observed here

25 Oct 2026 03:17:36 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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CVSS 3.1 · [email protected] · Secondary · 4.5 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

### Impact _**Native Mode (default)**_ Singularity's default native runtime allows users to apply restrictions to container processes using the apparmor or selinux Linux Security Modules (LSMs), via the `--security selinux:<label>` or `--security apparmor:<profile>` flags. LSM labels are written to process or thread `attrs/exec` under `/proc`. If a user relies on LSM restrictions to prevent malicious operations then, under certain circumstances, an attacker can redirect the LSM label write operation so that it is ineffective. This requires: * The attacker to cause the user to run a malicious container image that redirects the mount of `/proc` to the destination of a shared mount, either known to be configured on the target system, or that will be specified by the user when running the container. * Control of the content of the shared mount, for example through another malicious container which also binds it, or as a user with relevant permissions on the host system it is bound from. Note that Singularity does not attempt to prevent damaging operations, or container escape, from containers that are started as the host root user. When a non-root user starts a container any LSM writes to /proc are performed as that user. For these reasons, the denial-of-service and container escape attacks detailed in [runc CVE-2025-52881](https://github.com/opencontainers/runc/security/advisories/GHSA-cgrx-mc8f-2prm) are not relevant. Processes running in non-root containers are subject to the standard permissions for the non-root account used, and cannot escalate privilege, even when intended container-specific LSM labels are not correctly applied. In addition, a bug in the detection of selinux support in Singularity's default setuid flow means that `--security selinux:<label>` flags may not be applied, even in the absence of an attack - but in this case a warning message is emitted, indicating that selinux is unavailable. This warning may be may be overlooked, mis-interpreted, or not seen when singularity is run from a script or other tool. Failure to apply requested restrictions should result in a fatal error, rather than a warning message. _**OCI-Mode**_ Singularity's OCI-mode is unaffected as it does not currently support applying LSM restrictions via the `--security` flag. ### Patches Ineffective write of selinux process labels is addressed via an update to the containers/selinux dependency in https://github.com/sylabs/singularity/pull/3850. This update brings in the upstream fix for CVE-2025-52881 in this dependency. Ineffective write of apparmor process labels is addressed in commit 5af3e79. Failure to detect apparmor / selinux support, when `--security` flags are provided, is made an error rather than a warning in commit 2788296. ### Workarounds There are no known workarounds, other than to define system-wide apparmor / selinux policy for Singularity itself. This would apply to all containers, not just those run with the `--security` flags. Additionally, restrictions that are reasonable to apply to container processes may impact the functionality of Singularity. ### References Related vulnerabilities in runc: * [runc CVE-2025-52881](https://github.com/opencontainers/runc/security/advisories/GHSA-cgrx-mc8f-2prm) * [runc CVE-2019-19921](https://github.com/advisories/GHSA-fh74-hm69-rqjw)

Source published

2 Dec 2025 21:07:02 UTC

Source modified

4 Feb 2026 04:21:29 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

Publisher rating · MODERATE

Singularity ineffectively applies of selinux / apparmor LSM process labels in github.com/sylabs/singularity. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/sylabs/singularity/v4 before v4.1.11.

Source published

8 Dec 2025 21:31:36 UTC

Source modified

3 Mar 2026 04:57:44 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.