GHSA-hhfg-fwrw-87w7 · Severity: low · Ecosystem: pip — sigstore has insufficient validation of integration timestamp during verification
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.
Conclusion & alert: CVE-2024-55655 is rated Low Risk (19.9/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.09%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-02-06 | 0.15% | 0.09% | -0.06% |
| 2 | 2026-01-18 | 0.05% | 0.15% | +0.10% |
| 3 | 2025-11-21 | — | 0.05% | — |
Full EPSS history (9 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 2.7 | 4.0 | LOW |
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— | — | [email protected] |
GHSA-hhfg-fwrw-87w7 · Severity: low · Ecosystem: pip — sigstore has insufficient validation of integration timestamp during verification
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| No affected products in dataset. | |||