CVE-2026-44246Public exploitNetwork attack vector

Authenticated issue manipulation via untrusted Claude prompts

Published May 12, 2026 · Updated May 12, 2026

LLM prompt injection in nnU-Net before 2.4.1 allows remote authenticated users to alter issue comments and labels via crafted issues. The issue-triage workflow embeds untrusted issue titles and bodies in the operative Claude prompt while granting the agent authenticated gh comment and label commands. Opening an issue triggers the workflow automatically, so any GitHub user able to create issues can steer repository actions on that issue but cannot affect service availability.

CVSS severity7.2
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

LLM prompt injection in nnU-Net before 2.4.1 allows remote authenticated users to alter issue comments and labels via crafted issues. The issue-triage workflow embeds untrusted issue titles and bodies in the operative Claude prompt while granting the agent authenticated gh comment and label commands. Opening an issue triggers the workflow automatically, so any GitHub user able to create issues can steer repository actions on that issue but cannot affect service availability.

The record

CVE
CVE-2026-44246
Published
May 12, 2026
Updated
May 12, 2026
Vendor
German Cancer Research Center (DKFZ)
Product
nnU-Net
Classifications
CWE-1427
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=< 2.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

German Cancer Research Center (DKFZ) · nnU-Netversion=< 2.4.1

Published CVSS scores

7.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1427Improper Neutralization of Input Used for LLM Prompting

Public exploit references

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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