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Fencer Vulns
medium 5.4

CVE-2026-48758 json

sigstore-js: DSSE payloadType type-binding failure

published 2026-06-26 4 mo ago modified 2026-10-24 15 d ago also GHSA-jfc7-64v2-mr8c , EUVD-2026-44501

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

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.

Patch / fix

  • npm @sigstore/core 3.2.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-48758 updated cvss 5.4

sigstore-core: @sigstore/core: Signature bypass due to incorrect encoding in preAuthEncoding

  • Red Hat Enterprise Linux 8 sigstore 3.1.0 Red Hat Enterprise Linux 9 sigstore 3.1.0 Red Hat Enterprise Linux 10 sigstore 3.1.0 Red Hat Enterprise Linux AI (RHEL AI) 3 sigstore 3.1.0 Red Hat OpenShift Dev Spaces sigstore 3.1.0 Red Hat Satellite 6 sigstore 3.1.0
    +1 more products
    Red Hat Self-service automation portal 2 sigstore 3.1.0
    affected: workaround, no fix available “Upgrade to @sigstore/core 3.2.1 or later.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sigstore/sigstore-js/security/advisories/GHSA-jfc7-64v2-mr8c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

Affected packages

ecosystem package affected fixed in
npm @sigstore/core
<3.2.1
3.2.1

Affected products

  • sigstore sigstore-js

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.