CVE-2026-49834Network attack vector

Trust-policy bypass via duplicate log witness counting

Published Jul 17, 2026 · Updated Jul 17, 2026

Cryptographic verification bypass in Sigstore sigstore-go before 1.2.0 allows remote attackers to defeat multi-log trust policies. VerifySignedCertificateTimestamp and VerifyTlogEntry count repeated SCT paths or entries without deduplicating the originating log authority. Exploitation requires a threshold above one and control of one trusted transparency or CT log; accepted artifacts can then violate the intended integrity policy.

CVSS severity5.9
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic verification bypass in Sigstore sigstore-go before 1.2.0 allows remote attackers to defeat multi-log trust policies. VerifySignedCertificateTimestamp and VerifyTlogEntry count repeated SCT paths or entries without deduplicating the originating log authority. Exploitation requires a threshold above one and control of one trusted transparency or CT log; accepted artifacts can then violate the intended integrity policy.

The record

CVE
CVE-2026-49834
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
Sigstore
Product
sigstore-go
Classifications
CWE-347, T1553
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sigstore · sigstore-goversion=< 1.2.0

Published CVSS scores

5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1553Subvert Trust Controls

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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