Last updated: July 5, 2026 at 9:01 AM UTC
All 557 Vulnerability 199 Breach 106 Threat 245 Defense 7
Tag: github-actions (4 articles)Clear

Cordyceps CI/CD weakness lets anonymous pull requests hijack build pipelines

Researchers at Novee disclosed Cordyceps, a systemic class of weaknesses in CI/CD pipelines, especially GitHub Actions workflows, that lets an attacker with nothing more than a free account hijack a project's build and release process. The danger is not a single bug but how workflows chain together: an untrusted pull request or comment feeds a low-privilege workflow whose output flows into a higher-privilege one, ending in stolen credentials, poisoned artifacts, or malicious releases. A scan of 30,000 repositories found over 300 fully exploitable, with fixes confirmed by Microsoft, Google, Apache, Cloudflare, and the Python Software Foundation. Standard scanners miss it because they check files in isolation.

Check
Audit your GitHub Actions and other CI/CD workflows for steps that pass untrusted pull-request or comment data into higher-privilege jobs, and inventory where workflow tokens grant cloud or registry access.
Affected
Organizations whose CI/CD pipelines run workflows triggered by untrusted pull requests or comments, particularly GitHub Actions setups where low-privilege and high-privilege jobs share data and tokens across trust boundaries.
Fix
Treat workflow files as security-critical code, apply least privilege to workflow tokens, isolate untrusted pull-request triggers, sanitize data crossing between jobs, and review CI/CD changes generated by AI coding tools.

Claude Code GitHub Action flaw let one malicious issue hijack repos via prompt injection and OIDC token theft - bot-trigger bypass

Researcher RyotaK has disclosed a now-patched flaw in Anthropic's Claude Code GitHub Action, which drops Claude into CI/CD to triage issues and review PRs with broad repo permissions. The action's trigger check waved through any actor whose name ended in [bot] - but anyone can register a GitHub App and use its token to open an issue on a public repo. Agent mode lacked the human-actor check tag mode had. The attacker then used indirect prompt injection in an issue to make Claude read /proc/self/environ and write back the OIDC credentials, which can be replayed for an installation token with write access. Anthropic's example workflow shipped with allowed_non_write_users: '*'.

Check
Audit repos using Claude Code GitHub Action: update to the patched version, and check workflows for allowed_non_write_users set to '*'. Review public run summaries for leaked secrets.
Affected
Repositories using vulnerable Claude Code GitHub Action versions, especially in agent mode or with allowed_non_write_users: '*' copied from Anthropic's example. Public repos are exposed to [bot]-triggered prompt-injection attacks.
Fix
Update the Claude Code action to the fixed release. Remove allowed_non_write_users: '*', restrict triggers to write-access humans, and rotate any OIDC-derived tokens. Avoid posting task output to public run summaries.

Megalodon GitHub Actions attack scans 5,561 repos for CI/CD secrets; polymarketdev publishes nine wallet-stealer npm packages

SafeDep has detailed Megalodon, a GitHub Actions attack that scans 5,561 repositories for usable CI/CD secrets and credentials by submitting malicious pull requests that contain crafted workflow files. The campaign appears unrelated to the recent TeamPCP supply-chain wave. Separately, a throwaway npm account 'polymarketdev' published nine packages within 30 seconds (polymarket-trading-cli, polymarket-terminal, polymarket-trade, polymarket-auto-trade, polymarket-copy-trading, polymarket-bot, polymarket-claude-code, polymarket-ai-agent, polymarket-trader) that, on postinstall, present a fake wallet onboarding prompt and exfiltrate Ethereum and Polygon private keys to a Cloudflare Worker at polymarketbot.polymarketdev.workers[.]dev. The malicious packages remain live on npm at time of publication.

Check
Search GitHub Actions audit logs for unfamiliar workflow files added via pull requests since May 21. Search npm install logs for any polymarket-* package.
Affected
5,561 GitHub repositories specifically targeted by Megalodon malicious pull requests. Any Ethereum or Polygon developer who installed polymarket-* npm packages exposed wallet keys.
Fix
Restrict workflows triggered by pull_request_target. Pin GitHub Actions to full commit SHAs not tags. Treat any system that ran polymarket-* packages as compromised; rotate wallet keys immediately.

Shai-Hulud wave: 600+ npm @antv packages compromised in one hour, GitHub Action 'actions-cool' tag hijack linked

Between 01:56 and 02:56 UTC on May 19, a Shai-Hulud-flavored attack published 639 malicious versions across 323 npm packages, mostly in the @antv chart and graph namespace, after compromising the maintainer account 'atool.' Affected libraries include @antv/g2, @antv/g6, echarts-for-react, timeago.js, and jest-canvas-mock (still 10M monthly downloads despite three years dormant). A linked attack hijacked 15 tags of the 'actions-cool' GitHub Action and replaced them with a credential stealer that reads runner memory and exfils to t.m-kosche[.]com - the same domain as the @antv campaign. Socket and Aikido say there are now 2,900+ GitHub repos generated by this wave.

Check
Audit package lockfiles and CI logs for installs of any @antv/* package or timeago.js, size-sensor, jest-canvas-mock, echarts-for-react published on May 19. Search workflows for 'actions-cool/maintain-one-comment@<tag>' references.
Affected
Developers and CI/CD pipelines that installed @antv packages or used the actions-cool GitHub Actions between May 19 01:56 UTC and the npm registry takedown.
Fix
Pin GitHub Actions to full commit SHAs, not tags. Block egress to t.m-kosche.com. Rotate every developer token, npm token, cloud credential, and SSH key on machines that ran affected builds.