What is CVE-2021-3538?

CVE-2021-3538 is a critical-severity security vulnerability in github.com/satori/go.uuid (go), affecting versions >= 1.2.1-0.20180103161547-0ef6afb2f6cd, < 1.2.1-0.20180404165556-75cca531ea76. It is fixed in 1.2.1-0.20180404165556-75cca531ea76.

How severe is CVE-2021-3538?

CVE-2021-3538 has a CVSS score of 9.8 (Critical). 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/satori/go.uuid are affected by CVE-2021-3538?

github.com/satori/go.uuid (go) versions >= 1.2.1-0.20180103161547-0ef6afb2f6cd, < 1.2.1-0.20180404165556-75cca531ea76 is affected.

Is there a fix for CVE-2021-3538?

Yes. CVE-2021-3538 is fixed in 1.2.1-0.20180404165556-75cca531ea76. Upgrade to this version or later.

Is CVE-2021-3538 exploitable, and should I be worried?

Whether CVE-2021-3538 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-2021-3538 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-2021-3538?

Upgrade github.com/satori/go.uuid to 1.2.1-0.20180404165556-75cca531ea76 or later.

CVE-2021-3538 in github.com/satori/go.uuid

Q: How severe is CVE-2021-3538?

CVE-2021-3538 has a CVSS score of 9.8 (Critical). 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/satori/go.uuid are affected by CVE-2021-3538?

github.com/satori/go.uuid (go) versions >= 1.2.1-0.20180103161547-0ef6afb2f6cd, < 1.2.1-0.20180404165556-75cca531ea76 is affected.

Q: Is there a fix for CVE-2021-3538?

Yes. CVE-2021-3538 is fixed in 1.2.1-0.20180404165556-75cca531ea76. Upgrade to this version or later.

Q: Is CVE-2021-3538 exploitable, and should I be worried?

Whether CVE-2021-3538 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-2021-3538 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-2021-3538?

Upgrade github.com/satori/go.uuid to 1.2.1-0.20180404165556-75cca531ea76 or later.

Summary

go.uuid has Predictable UUID Identifiers

CVE Description for go.uuid

A flaw was found in github.com/satori/go.uuid in versions from commit 0ef6afb2f6cdd6cdaeee3885a95099c63f18fc8c to d91630c8510268e75203009fe7daf2b8e1d60c45. Due to insecure randomness in the g.rand.Read function the generated UUIDs are predictable for an attacker.

Update on 19 September 2024 -- This vulnerability never existed in sif

The official NIST CVE-2021-3538 record says:

A flaw was found in github.com/satori/go.uuid in versions from commit 0ef6afb2f6cdd6cdaeee3885a95099c63f18fc8c to d91630c8510268e75203009fe7daf2b8e1d60c45.

That commit and that fix were never in a tagged release of satori/go.uuid, and prior to this announcement sif had used the last tag, 1.2.0. The NIST record says version 1.2.0 was vulnerable, but that's not true. So sif was never vulnerable to this. Also, beginning with version 2.0.0, sif does not use satori/go.uuid anymore.

This update was made in response to issue #243 which has more details.

The original, incorrect sif vulnerability description is below.

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 -u github.com/satori/[email protected]

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 https://github.com/hpcng/sif/issues

Impact

The siftool new command produces predictable UUID identifiers due to insecure randomness in the version of the github.com/satori/go.uuid module used as a dependency.

CVE-2021-3538 has a CVSS score of 9.8 (Critical). 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 (1.2.1-0.20180404165556-75cca531ea76); upgrading removes the vulnerable code path.

Affected versions

github.com/satori/go.uuid (>= 1.2.1-0.20180103161547-0ef6afb2f6cd, < 1.2.1-0.20180404165556-75cca531ea76)

Security releases

github.com/satori/go.uuid → 1.2.1-0.20180404165556-75cca531ea76 (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.

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Remediation advice

A patch is available in version >= v1.2.2 of the module. Users are encouraged to upgrade.

Fixed by https://github.com/hpcng/sif/pull/90

Frequently Asked Questions

What is CVE-2021-3538? CVE-2021-3538 is a critical-severity security vulnerability in github.com/satori/go.uuid (go), affecting versions >= 1.2.1-0.20180103161547-0ef6afb2f6cd, < 1.2.1-0.20180404165556-75cca531ea76. It is fixed in 1.2.1-0.20180404165556-75cca531ea76.
How severe is CVE-2021-3538? CVE-2021-3538 has a CVSS score of 9.8 (Critical). 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/satori/go.uuid are affected by CVE-2021-3538? github.com/satori/go.uuid (go) versions >= 1.2.1-0.20180103161547-0ef6afb2f6cd, < 1.2.1-0.20180404165556-75cca531ea76 is affected.
Is there a fix for CVE-2021-3538? Yes. CVE-2021-3538 is fixed in 1.2.1-0.20180404165556-75cca531ea76. Upgrade to this version or later.
Is CVE-2021-3538 exploitable, and should I be worried? Whether CVE-2021-3538 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-2021-3538 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-2021-3538? Upgrade github.com/satori/go.uuid to 1.2.1-0.20180404165556-75cca531ea76 or later.