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The CVE-2026-40913 vulnerability arises from an insufficient permission check within Apache Magpie’s agent-assisted security-issue handling workflow, specifically in the skill that synchronizes security issues across GitHub, mailing lists, and pull requests. When an agent session is initiated with a limited-privilege token, the skill’s proposal-before-apply mechanism fails to validate whether the token’s scope includes read access to the private security tracker that holds pre-disclosure CVE content. Because the skill fetches issue bodies, comments, and linked PR metadata without verifying the token’s DAG-level or repository-level read permissions, an attacker who can influence the agent’s input—such as by crafting a malicious mailing-list message or a public issue —can cause the agent to retrieve and display sensitive information from repositories and trackers outside the token’s authorized scope. The vulnerability is rooted in the agent host’s trust model, which assumes that the configured egress allowlist and the user’s explicit confirmation steps are sufficient to prevent unauthorized data access, but does not enforce per-resource authorization checks when the skill queries the GitHub API or the private tracker. In practice, the agent’s “observed-state dump” and its regeneration of CVE JSON attachments may include issue s, descriptions, and comment threads from trackers that the token should not be able to read, effectively leaking the existence and names of embargoed vulnerabilities. The flaw is classified as a medium-severity access control bypass because it requires the attacker to have some ability to inject content into a channel that the agent processes (e.g., a public mailing list or a GitHub issue that the skill syncs), and because the exposed data is limited to metadata and discussion text rather than exploit code or credentials. However, in the context of Apache Magpie’s security-issue lifecycle, which handles 16 steps from intake through CVE publication, the exposure of pre-disclosure CVE details can accelerate targeted attacks before a patch is available. The vulnerability affects the security-issue-sync skill and any adopter configuration that uses a single token with broader read permissions than the specific tracker it is meant to serve. The fix recommended by the Magpie maintainers involves adding an explicit authorization gate that checks the token’s scope against the tracker’s repository access level before any data is fetched, and rejecting the sync operation if the token lacks the required read permission. Users are advised to upgrade to a patched version of the framework, which enforces per-repository permission validation in the agent host’s egress layer and logs any attempted access to unauthorized resources. The CVE was assigned by the Apache Software Foundation’s CNA and published through the Vulnogram workflow that Magpie itself automates.
DailyCVE Form:
Platform: Apache Magpie
Version: 0.1.0
Vulnerability: Agent-assisted lifecycle
Severity: Medium
date: 2026-10-05
Prediction: 2026-11-05
What Undercode Say:
Analytics: The vulnerability affects adopter configurations that use broad-scope tokens. Monitoring agent logs for unauthorized tracker access attempts can reveal exploitation. Bash commands such as `gh api /repos/
Exploit: (Educational Purposes!)
An attacker with the ability to post a message to a public mailing list that the agent monitors can craft a message body containing a reference to a private tracker issue number, such as Fixes 1234 in private-tracker. When the security-issue-sync skill runs, it fetches the referenced issue from the private tracker without verifying the token’s read permissions, and includes the issue and description in its observed-state dump. The attacker can then infer the existence of an embargoed vulnerability and its affected component from the leaked metadata. The exploit does not require direct access to the private tracker; it relies solely on the agent’s over-permissive data fetching.
Protection: from this CVE
Adopters should upgrade to a patched version of Apache Magpie that includes explicit per-repository authorization checks in the security-issue-sync skill. Until the patch is available, configure the agent host to use a separate, least-privilege token for each tracker and ensure that the egress allowlist restricts API calls to only the repositories that the token is authorized to read. Additionally, review the skill’s proposal-before-apply output for any references to unauthorized trackers before confirming the sync. The Magpie maintainers recommend running `npx skills add https://github.com/apache/magpie –skill generate-cve-json` only after verifying that the token’s scope matches the tracker’s DAG read permissions.
Impact:
The impact of CVE-2026-40913 is the potential disclosure of pre-disclosure CVE metadata, including issue s, affected versions, and discussion threads from private security trackers. This can give attackers advance knowledge of unpatched vulnerabilities, enabling them to develop exploits before a fix is released. The vulnerability also undermines the trust model of agent-assisted maintainership, as adopters may unknowingly expose embargoed content through routine security-issue synchronization. The medium severity reflects the limited scope of the data exposed (metadata rather than exploit code) and the requirement for the attacker to inject content into a monitored channel, but the impact on supply-chain integrity is significant because it can accelerate targeted attacks against downstream users.
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Sources:
Reported By: github.com
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