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Path Traversal

CVE-2026-82427

CVE-2026-82427 — Apache Storm Nimbus: Path Traversal as the Supervisor User via Unsanitised Blobstore Map Local Name

Description A topology's `topology.blobstore.map` lets the submitter choose a local name for each blob that the supervisor localises. That name was used to build a path under the topology's working directory without normalisation, in both `AsyncLocalizer` and `Container.createBlobstoreLinks`, and the symlink helper force-deletes whatever already exists at the target before creating the link. A submitter could therefore use `../` segments to direct that delete-and-symlink operation at an arbitrary path, as the supervisor user, on every node the topology is scheduled onto. The consequences include recursive deletion of supervisor-owned content and planting a symlink that causes a subsequent worker launch to execute attacker-chosen code as another tenant's operating-system user, which defeats the isolation that `supervisor.run.worker.as.user` is intended to provide. Mitigation Upgrade to 3.1.0, where the resolved target must lie inside the expected root at both call sites. Users who cannot upgrade immediately should restrict topology submission to trusted principals, and may reject submissions whose `topology.blobstore.map` entries contain path separators or `..` segments before they reach Nimbus. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

Published Updated Sources: NVD, Apache Software Foundation (CNA), GitHub, GitHub Security Advisory, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

ahead of 0% of scored CVEs

Affects

Apache

Apache Storm Nimbus

CVSS base

Unscored

no source published a base score

Remediation

The vendor's own words where we have them.

Upgrade Apache Storm Nimbus to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

  • Identify exposed assets running affected vendor/product/version combinations.
  • Prioritize based on EPSS, PoC availability, and external exposure.
  • Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

VendorProductVersionsStatus
ApacheApache Storm Nimbus3.0.0 to < 3.1.0Vulnerable

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

  • Execute Unauthorized Code or Commands
  • Modify Files or Directories
  • Read Files or Directories
  • DoS: Crash, Exit, or Restart

Mitigation: Assume all input is malicious. Use an accept known good input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, boat may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as red or blue. Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single . character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as / to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering / is insufficient protection if the filesystem also supports the use of as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if ../ sequences are removed from the .../...// string in a sequential fashion, two instances of ../ would be removed from the original string, but the remaining characters would still form the ../ string.

Weakness & attack patterns

  • CWE-22Path Traversal

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-126 · Path TraversalCAPEC-76 · Manipulating Web Input to File System CallsCAPEC-79 · Using Slashes in Alternate EncodingCAPEC-64 · Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-78 · Using Escaped Slashes in Alternate Encoding

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026

  2. Initial · CVE published

    Sep 14, 2026 · NVD

  3. Added · GHSA-mmm4-x298-c649 published (unknown)

    Sep 14, 2026 · GitHub Security Advisory

  4. CVE published by MITRE.

    Sep 14, 2026 · SOCRadar CTI

Source activity

Readings a source repeats on a schedule, counted rather than listed.

  • 1×Tweets · 1 time tweeted.Sep 14, 2026 · SOCRadar CTI

References

3 on the record

Coverage

1 story from the feeds we poll

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1

What should defenders know first?

CVE-2026-82427 is Apache Storm Nimbus: Path Traversal as the Supervisor User via Unsanitised Blobstore Map Local Name, a unscored vulnerability affecting Apache Storm Nimbus from Apache Software Foundation. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-82427. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-82427. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS null describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.