What is CVE-2021-29499?

CVE-2021-29499 is a high-severity use of insufficiently random values vulnerability in github.com/sylabs/sif (go), affecting versions < 1.2.3. It is fixed in 1.2.3. Security-sensitive operations rely on values that are predictable or insufficiently random.

How severe is CVE-2021-29499?

CVE-2021-29499 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of github.com/sylabs/sif are affected by CVE-2021-29499?

github.com/sylabs/sif (go) versions < 1.2.3 is affected.

Is there a fix for CVE-2021-29499?

Yes. CVE-2021-29499 is fixed in 1.2.3. Upgrade to this version or later.

Is CVE-2021-29499 exploitable, and should I be worried?

Whether CVE-2021-29499 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2021-29499 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2021-29499?

Upgrade github.com/sylabs/sif to 1.2.3 or later.

CVE-2021-29499 in github.com/sylabs/sif

Q: How severe is CVE-2021-29499?

CVE-2021-29499 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of github.com/sylabs/sif are affected by CVE-2021-29499?

github.com/sylabs/sif (go) versions < 1.2.3 is affected.

Q: Is there a fix for CVE-2021-29499?

Yes. CVE-2021-29499 is fixed in 1.2.3. Upgrade to this version or later.

Q: Is CVE-2021-29499 exploitable, and should I be worried?

Whether CVE-2021-29499 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2021-29499 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2021-29499?

Upgrade github.com/sylabs/sif to 1.2.3 or later.

Summary

Predictable SIF UUID Identifiers in github.com/sylabs/sif

Workarounds

Users passing CreateInfo struct should ensure the ID field is generated using a version of github.com/satori/go.uuid that is not vulnerable to this issue. Unfortunately, the latest tagged release is vulnerable to this issue. One way to obtain a non-vulnerable version is:

go get github.com/satori/go.uuid@75cca531ea763666bc46e531da3b4c3b95f64557

References

https://github.com/satori/go.uuid/issues/73

For more information

If you have any questions or comments about this advisory:

Open an issue in github.com/sylabs/sif
Email us at [email protected]

Impact

The siftool new command and func siftool.New() produce predictable UUID identifiers due to insecure randomness in the version of the github.com/satori/go.uuid module used as a dependency.

Security-sensitive operations rely on values that are predictable or insufficiently random. Typical impact: forged tokens, guessable identifiers, or broken cryptographic protocols.

CVE-2021-29499 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.2.3); upgrading removes the vulnerable code path.

Affected versions

github.com/sylabs/sif (< 1.2.3)

Security releases

github.com/sylabs/sif → 1.2.3 (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

Already deployed Kodem?

See it in your environment New to Kodem? Get a demo →

Remediation advice

A patch is available in version >= v1.2.3 of the module. Users are encouraged to upgrade.

The patch is commit https://github.com/sylabs/sif/commit/193962882122abf85ff5f5bcc86404933e71c07d

Frequently Asked Questions

What is CVE-2021-29499? CVE-2021-29499 is a high-severity use of insufficiently random values vulnerability in github.com/sylabs/sif (go), affecting versions < 1.2.3. It is fixed in 1.2.3. Security-sensitive operations rely on values that are predictable or insufficiently random.
How severe is CVE-2021-29499? CVE-2021-29499 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of github.com/sylabs/sif are affected by CVE-2021-29499? github.com/sylabs/sif (go) versions < 1.2.3 is affected.
Is there a fix for CVE-2021-29499? Yes. CVE-2021-29499 is fixed in 1.2.3. Upgrade to this version or later.
Is CVE-2021-29499 exploitable, and should I be worried? Whether CVE-2021-29499 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2021-29499 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2021-29499? Upgrade github.com/sylabs/sif to 1.2.3 or later.