How severe is CVE-2021-27099?

CVE-2021-27099 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-27099 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27099?

CVE-2021-27099 affects Cncf Spire. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27099?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-27099 published?

CVE-2021-27099 was published on 2021-03-05 and last updated on 2026-06-17.

CVE-2021-27099

CVE-2021-27099 is a medium-severity vulnerability in Cncf Spire with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 4.9
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Cncf Spire
Published: 2021-03-05
Last modified: 2026-06-17

Description

In SPIRE before versions 0.8.5, 0.9.4, 0.10.2, 0.11.3 and 0.12.1, the "aws_iid" Node Attestor improperly normalizes the path provided through the agent ID templating feature, which may allow the issuance of an arbitrary SPIFFE ID within the same trust domain, if the attacker controls the value of an EC2 tag prior to attestation, and the attestor is configured for agent ID templating where the tag value is the last element in the path. This issue has been fixed in SPIRE versions 0.11.3 and 0.12.1

Frequently asked questions

What is CVE-2021-27099?: In SPIRE before versions 0.8.5, 0.9.4, 0.10.2, 0.11.3 and 0.12.1, the "aws_iid" Node Attestor improperly normalizes the path provided through the agent ID templating feature, which may allow the issuance of an arbitrary SPIFFE ID within the same trust domain, if the attacker controls the value of an EC2 tag prior to attestation, and the attestor is configured for agent ID templating where the tag value is the last element in the path. This issue has been fixed in SPIRE versions 0.11.3 and 0.12.1
How severe is CVE-2021-27099?: CVE-2021-27099 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-27099 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27099?: CVE-2021-27099 affects Cncf Spire. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27099?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-27099 published?: CVE-2021-27099 was published on 2021-03-05 and last updated on 2026-06-17.

References

https://github.com/spiffe/spire/security/advisories/GHSA-q7gm-mjrg-44h9

Affected products (1)

cpe:2.3:a:cncf:spire:*:*:*:*:*:*:*:*

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