Vulnerability · Published Jul 14, 2026 · Assigned by GitHub_M

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

Medium 5.4

In plain English

A medium-severity security flaw in sigstore-js from sigstore. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.2%top 85.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	@sigstore/core	3.2.1	GHSA-jfc7-64v2-mr8c

Affected products (as reported)

Vendor	Product	Versions
sigstore	sigstore-js	< 3.2.1

Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

References

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