Medium [CVE-2026-48758] @sigstore/core: Signature bypass due to incorrect encoding in preAuthEncoding
This medium-severity Red Hat Linux advisory covers CVE-2026-48758 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.
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Summary
sigstore-js provides JavaScript libraries for interacting with Sigstore services.
Prior to 3.2.1, the preAuthEncoding function in @sigstore/core uses Node.js ascii encoding when converting the PAE string to bytes, allowing payloadType to be mutated after signing without invalidating the signature and breaking the type-binding guarantee that DSSE is designed to provide. This issue is fixed in version 3.2.1.
This encoding truncates Unicode characters to their low byte, allowing an attacker to substitute characters in the payloadType with Unicode variants that produce identical PAE bytes.
As a result, the payloadType can be mutated after a digital signature has been applied without invalidating the signature, thereby bypassing the intended type-binding guarantee of the Digital Signature Standard for Entity Authentication (DSSE). Red Hat severity: Moderate — CVSS 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L).
Weakness: CWE-347. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux AI (RHEL AI) 3; Red Hat OpenShift Dev Spaces; Red Hat Satellite 6; Self-service automation portal 2.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: sigstore.
- < 3.2.1
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
Mitigation checklist
- Upgrade to @sigstore/core 3.2.1 or later.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
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