High severity · published Jul 17, 2026
CVE-2026-49834
sigstore-go: Multi-log threshold bypass via single compromised log
7.5
CVSS
0.2%
EPSS
No
On KEV
Description
sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.0, a verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) counts verified witnesses per entry or per validation path rather than per log authority, allowing a single compromised transparency log or CT log to satisfy multi-log threshold requirements and defeat the multi-log policy. This issue is fixed in version 1.2.0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
sigstore-go · sigstore
< 1.2.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49834
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49834
Patch
https://github.com/sigstore/sigstore-go/commit/dbb07e62623edd5b175fb9dd5a41dcb85a159207
Issue Tracking
https://github.com/sigstore/sigstore-go/pull/633
Product
https://github.com/sigstore/sigstore-go/releases/tag/v1.2.0
Vendor Advisory
https://github.com/sigstore/sigstore-go/security/advisories/GHSA-9vcr-p3rj-q5q6
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