How severe is CVE-2025-64750?

CVE-2025-64750 has a CVSS score of 4.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2025-64750?

CVE-2025-64750 affects the following packages: github.com/sylabs/singularity/v4 (Go), github.com/sylabs/singularity/v4 (Go). Ecosystems affected: Go.

How do I fix CVE-2025-64750?

Update github.com/sylabs/singularity/v4 to 4.3.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-64750 is resolved across your whole dependency graph.

How do I detect CVE-2025-64750 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sylabs/singularity/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-64750 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2025-64750 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-64750 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-64750?

CVE-2025-64750 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 7th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-64750?

CVE-2025-64750 is classified as CWE-61 (CWE-61), CWE-706 (CWE-706). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-64750 published, and has it been updated?

CVE-2025-64750 was published on December 2, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2025-64750 — singularity

MEDIUMFix: sylabs/singularity@2788296

CVE-2025-64750 is a medium-severity (CVSS 4.5) CWE-61 vulnerability in github.com/sylabs/singularity/v4. A fix is available for github.com/sylabs/singularity/v4 — see the affected versions and patch details below.

Singluarity ineffectively applies of selinux / apparmor LSM process labels

Also known asGHSA-wwrx-w7c9-rf87GO-2025-4177

Published

Dec 2, 2025

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-64750.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk+0.01%

Lower risk than most CVEs7th percentile — riskier than 7% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🐹github.com/sylabs/singularity/v4🐹github.com/sylabs/singularity/v4

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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 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:

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/sylabs/singularity/v4`	≥ 4.2.0-rc.1&&< 4.3.5	4.3.5`go get github.com/sylabs/singularity/v4@v4.3.5`
🐹Go	`github.com/sylabs/singularity/v4`	all versions	4.1.11`go get github.com/sylabs/singularity/v4@v4.1.11`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sylabs/singularity/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/sylabs/singularity/v4 to 4.3.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-64750 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### 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 malicio