CVE-2024-55655
sigstore-python has insufficient validation of integration timestamp during verification
Published Dec 10, 2024
CVSS 4.0 · 2.7 Low
EPSS < 1%
KEV · Not listed
Description
sigstore-python is a Python tool for generating and verifying Sigstore signatures. Versions of sigstore-python newer than 2.0.0 but prior to 3.6.0 perform insufficient validation of the "integration time" present in "v2" and "v3" bundles during the verification flow: the "integration time" is verified *if* a source of signed time (such as an inclusion promise) is present, but is otherwise trusted if no source of signed time is present. This does not affect "v1" bundles, as the "v1" bundle format always requires an inclusion promise.
Sigstore uses signed time to support verification of signatures made against short-lived signing keys. The impact and severity of this weakness is *low*, as Sigstore contains multiple other enforcing components that prevent an attacker who modifies the integration timestamp within a bundle from impersonating a valid signature. In particular, an attacker who modifies the integration timestamp can induce a Denial of Service, but in no different manner than already possible with bundle access (e.g. modifying the signature itself such that it fails to verify). Separately, an attacker could upload a *new* entry to the transparency service, and substitute their new entry's time. However, this would still be rejected at validation time, as the new entry's (valid) signed time would be outside the validity window of the original signing certificate and would nonetheless render the attacker auditable.
Sigstore uses signed time to support verification of signatures made against short-lived signing keys. The impact and severity of this weakness is *low*, as Sigstore contains multiple other enforcing components that prevent an attacker who modifies the integration timestamp within a bundle from impersonating a valid signature. In particular, an attacker who modifies the integration timestamp can induce a Denial of Service, but in no different manner than already possible with bundle access (e.g. modifying the signature itself such that it fails to verify). Separately, an attacker could upload a *new* entry to the transparency service, and substitute their new entry's time. However, this would still be rejected at validation time, as the new entry's (valid) signed time would be outside the validity window of the original signing certificate and would nonetheless render the attacker auditable.
Affected Products
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CVE record
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NVD configurations
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Red Hat packages
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OpenCVE enrichment
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| sigstore | sigstore-python | affected |
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Remediation
Tracking
Advisories
| Source | ID | Title |
|---|---|---|
 EUVD |
EUVD-2024-3479 | sigstore-python is a Python tool for generating and verifying Sigstore signatures. Versions of sigstore-python newer than 2.0.0 but prior to 3.6.0 perform insufficient validation of the "integration time" present in "v2" and "v3" bundles during the verification flow: the "integration time" is verified *if* a source of signed time (such as an inclusion promise) is present, but is otherwise trusted if no source of signed time is present. This does not affect "v1" bundles, as the "v1" bundle format always requires an inclusion promise. Sigstore uses signed time to support verification of signatures made against short-lived signing keys. The impact and severity of this weakness is *low*, as Sigstore contains multiple other enforcing components that prevent an attacker who modifies the integration timestamp within a bundle from impersonating a valid signature. In particular, an attacker who modifies the integration timestamp can induce a Denial of Service, but in no different manner than already possible with bundle access (e.g. modifying the signature itself such that it fails to verify). Separately, an attacker could upload a *new* entry to the transparency service, and substitute their new entry's time. However, this would still be rejected at validation time, as the new entry's (valid) signed time would be outside the validity window of the original signing certificate and would nonetheless render the attacker auditable. |
 Github GHSA |
GHSA-hhfg-fwrw-87w7 | sigstore has insufficient validation of integration timestamp during verification |
Metrics
Attack Vector Network
Attack Complexity Low
Privileges Required None
Attack Requirements None
User Interaction None
Vulnerable System Confidentiality Impact None
Vulnerable System Integrity Impact Low
Vulnerable System Availability Impact None
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
No CVSS v3.1
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.252% probability within 30 days)
Exploitation none
Automatable yes
Technical Impact partial
References
History
Jul 16, 2025 1:45 PM
Scoring metrics updated
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epss
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epss
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Dec 11, 2024 4:15 PM
Scoring metrics updated
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ssvc
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Dec 10, 2024 11:15 PM
Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | sigstore-python is a Python tool for generating and verifying Sigstore signatures. Versions of sigstore-python newer than 2.0.0 but prior to 3.6.0 perform insufficient validation of the "integration time" present in "v2" and "v3" bundles during the verification flow: the "integration time" is verified *if* a source of signed time (such as an inclusion promise) is present, but is otherwise trusted if no source of signed time is present. This does not affect "v1" bundles, as the "v1" bundle format always requires an inclusion promise. Sigstore uses signed time to support verification of signatures made against short-lived signing keys. The impact and severity of this weakness is *low*, as Sigstore contains multiple other enforcing components that prevent an attacker who modifies the integration timestamp within a bundle from impersonating a valid signature. In particular, an attacker who modifies the integration timestamp can induce a Denial of Service, but in no different manner than already possible with bundle access (e.g. modifying the signature itself such that it fails to verify). Separately, an attacker could upload a *new* entry to the transparency service, and substitute their new entry's time. However, this would still be rejected at validation time, as the new entry's (valid) signed time would be outside the validity window of the original signing certificate and would nonetheless render the attacker auditable. | |
| Title | sigstore-python has insufficient validation of integration timestamp during verification | |
| Weaknesses | CWE-20 CWE-325 |
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cvssV4_0
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Subscriptions
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