CVE-2026-34841 is a critical-severity (CVSS 9.8) CWE-494 vulnerability in @usebruno/cli. A fix is available for @usebruno/cli — see the affected versions and patch details below.
Axios npm Supply Chain Incident Impacting @usebruno/cli
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-34841.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-34841 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
@usebruno/cliReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
This is a supply chain attack involving compromised versions of the axios npm package, which introduced a hidden dependency deploying a cross-platform Remote Access Trojan (RAT).
Users of @usebruno/cli who ran npm install between 00:21 UTC and ~03:30 UTC on March 31, 2026 may have been impacted.
Potential impact includes:
- Execution of a malicious
postinstallscript - Remote Access Trojan (RAT) installation
- Exfiltration of credentials and sensitive data
Not impacted:
- Bruno desktop app users
- Users who installed outside the attack window
Patches
The compromised axios versions (1.14.1, 0.30.4) have been removed from npm, and new installations will now resolve to safe versions.
Additionally, Bruno has taken further hardening steps:
- Pinned
axiosto a known safe version to prevent accidental resolution to malicious releases - Fix implemented in: https://github.com/usebruno/bruno/pull/7632
Recommendation
If users installed @usebruno/cli during the affected window:
- Reinstall dependencies
- Rotate all credentials and secrets:
For additional guidance on securing your system, refer to this article: https://www.aikido.dev/blog/axios-npm-compromised-maintainer-hijacked-rat
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @usebruno/cli | all versions | 3.2.1npm install @usebruno/cli@3.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @usebruno/cli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @usebruno/cli to 3.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34841 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-34841 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-34841. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-34841 in your dependencies?
O3 Security finds CVE-2026-34841 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.