CVE-2023-33199Network attack vector

Request-thread panic via unchecked null signature fields

Published May 26, 2023 · Updated Jan 14, 2025

Reachable assertion in Sigstore Rekor before 1.2.0 allows remote attackers to interrupt a request thread via a malformed intoto entry. The intoto/v0.0.2 parser dereferences null signature, signature-content, or public-key fields instead of rejecting the proposed entry. No authentication or user interaction is required; recovery returns HTTP 500 to the triggering client while the service continues.

CVSS severity5.3
Medium
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Sigstore Rekor before 1.2.0 allows remote attackers to interrupt a request thread via a malformed intoto entry. The intoto/v0.0.2 parser dereferences null signature, signature-content, or public-key fields instead of rejecting the proposed entry. No authentication or user interaction is required; recovery returns HTTP 500 to the triggering client while the service continues.

The record

CVE
CVE-2023-33199
Published
May 26, 2023
Updated
Jan 14, 2025
Vendor
Sigstore
Product
Rekor
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 2025Record 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 · Rekorversion=< 1.2.0

Published CVSS scores

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-617Reachable Assertion
T1499.004Application or System Exploitation

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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