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Fencer Intel
medium 5.4

CVE-2026-48758 json

sigstore-js: DSSE payloadType type-binding failure

published 5mo ago modified 18d ago also EUVD-2026-44501 , GHSA-jfc7-64v2-mr8c

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 15%
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

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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
3mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-11).

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 Intel 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.

The maintainers of sigstore/sigstore-js published their own advisory on GitHub. Reviewed sources take precedence over it.