CVE-2026-48758: sigstore-js: DSSE payloadType type-binding failure

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-14 · updated 2026-10-24
Weakness: CWE-347

Description

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.

Affected products

sigstore-js: before 3.2.1

References

https://github.com/sigstore/sigstore-js/commit/b5aa4f1f8d2db0a9dfa6430fb114d9c2f1c304f7
https://github.com/sigstore/sigstore-js/pull/1657
https://github.com/sigstore/sigstore-js/releases/tag/%40sigstore%2Fcore%403.2.1
https://github.com/sigstore/sigstore-js/security/advisories/GHSA-jfc7-64v2-mr8c
https://github.com/sigstore/sigstore-js/security/advisories/GHSA-jfc7-64v2-mr8c

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