Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-66564 is a high-severity Amplification (CWE-405) vulnerability in Linuxfoundation Sigstore Timestamp Authority. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Network Denial of Service (T1498); ranked at the 37th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-5 (Denial-of-service Protection) and SC-6 (Resource Availability) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-201319
Vulnerability Data
Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Prior to 2.0.3, Function api.ParseJSONRequest currently splits (via a call to strings.Split) an optionally-provided OID (which is untrusted data) on periods. Similarly, function api.getContentType splits the Content-Type header (which…
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is also untrusted data) on an application string. As a result, in the face of a malicious request with either an excessively long OID in the payload containing many period characters or a malformed Content-Type header, a call to api.ParseJSONRequest or api.getContentType incurs allocations of O(n) bytes (where n stands for the length of the function's argument). This vulnerability is fixed in 2.0.3.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
SC-5 directly requires mechanisms to limit the effects of asymmetric resource exhaustion attacks such as amplification DoS.
SC-6 enforces resource quotas and priority allocation that reduce the impact of unauthenticated or low-effort resource requests.
Least-functionality disables unnecessary services or features that could be leveraged for amplification.
SC-7 boundary controls can filter or rate-limit traffic patterns that enable amplification without equivalent client work.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Resilience mechanisms such as rate limiting and load balancing directly constrain asymmetric resource use.
Capacity planning and monitoring maintain availability headroom against amplification attacks.
Network monitoring detects amplification traffic patterns but does not itself limit asymmetric consumption.
Runtime resource monitoring can surface excessive consumption yet does not enforce authorization or work proofs.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Stress-testing and demand-reduction tactics (e.g., bandwidth throttling) blunt amplification vectors that would otherwise let an attacker multiply resource consumption through a single request.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248553 OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-405
- V-248552 OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-405
Oracle Linux 9 (2 rules)
- V-271709 OL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-405
- V-271710 OL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-405
RHEL 8 (2 rules)
- V-230244 RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-405
- V-244525 RHEL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-405