CVE-2026-82429 Apache Storm Worker Launcher: Local Privilege Escalation to Root via a Time-of-Check Race in the Worker Launcher
A local attacker can escalate privileges to root by exploiting a race condition in the Apache Storm worker launcher during directory permission updates.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-82429?
CVE-2026-82429 is a high-severity vulnerability in Apache Storm Worker Launcher, published on 14 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Description
The setuid-root `worker-launcher` binary adjusts ownership and permissions of worker directories by walking the tree with FTS and calling `lchown` and `chmod` on each entry's full pathname while running with an effective uid of 0. Both syscalls re-resolve the path at the time of the call, after FTS has classified the entry, and the trees being walked are owned and writable by the untrusted topology user.
A tenant running code on a supervisor node could therefore replace an intermediate directory component with a symbolic link between classification and the privileged operation, redirecting the root-owned `lchown` or `chmod` at an arbitrary file on the host. The operation is repeatable at will, since crashing a worker forces a relaunch and blob updates re-run the walk, so a failed attempt costs the attacker nothing.
This crosses the boundary that `supervisor.run.worker.as.user` and container isolation are intended to enforce. It is the same defect class as the Hadoop container-executor issues from which this code derives.
Mitigation
Upgrade to 3.1.0, where the privileged walk operates on file descriptors it has already stat'd rather than on pathnames re-resolved at call time.
Users who cannot upgrade immediately should not run untrusted topology code on supervisors configured with `supervisor.run.worker.as.user`, since the launcher is the boundary being crossed. Note that the launcher must be rebuilt and reinstalled after upgrading; replacing the Java artifacts alone is not sufficient.
Credit
The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.
Weakness: CWE-367
Which versions are affected by CVE-2026-82429?
How do I fix CVE-2026-82429?
No fix has been published for CVE-2026-82429 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-82429 being exploited?
There is no known exploitation of CVE-2026-82429 in the wild and no public exploit code.
Sources
Also known as GHSA-qchc-32xg-c7w6.