CVE-2026-43965Public exploit

Arbitrary directory deletion via unsanitized package keys

Published Jun 2, 2026 · Updated Jun 2, 2026

Path traversal in Gleam before 1.17.0 allows attackers to delete arbitrary directories via a malicious package manifest. LocalPackages::read_from_disc accepts absolute and parent-relative package keys, paths.build_packages_package joins them to the build tree, and remove_dir_all recursively deletes the resulting path without verifying containment. Exploitation requires a victim to run gleam deps download in the crafted project, and deletion is limited to directories writable by that process.

CVSS severity5.6
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Gleam before 1.17.0 allows attackers to delete arbitrary directories via a malicious package manifest. LocalPackages::read_from_disc accepts absolute and parent-relative package keys, paths.build_packages_package joins them to the build tree, and remove_dir_all recursively deletes the resulting path without verifying containment. Exploitation requires a victim to run gleam deps download in the crafted project, and deletion is limited to directories writable by that process.

The record

CVE
CVE-2026-43965
Published
Jun 2, 2026
Updated
Jun 2, 2026
Vendor
Gleam
Product
Gleam
Classifications
CWE-22, T1204.002, T1485
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.18.0-rc1 <1.17.0
  2. Affected versionversion=ed7aec0484f10d60978b63788c8a6497590855ab <690ca069817bee5f77a28fc3e360627c1da19291
  3. Affected versionversion=v0.18.0-rc1-elixir-alpine <v1.17.0-elixir-alpine
  4. Affected versionversion=v0.18.0-rc1-elixir-slim <v1.17.0-elixir-slim
  5. Affected versionversion=v0.18.0-rc1-elixir <v1.17.0-elixir
  6. Affected versionversion=v0.18.0-rc1-erlang-alpine <v1.17.0-erlang-alpine
  7. Affected versionversion=v0.18.0-rc1-erlang-slim <v1.17.0-erlang-slim
  8. Affected versionversion=v0.18.0-rc1-erlang <v1.17.0-erlang
  9. Affected versionversion=v0.18.0-rc1-node-alpine <v1.17.0-node-alpine
  10. Affected versionversion=v0.18.0-rc1-node-slim <v1.17.0-node-slim
  11. Affected versionversion=v0.18.0-rc1-node <v1.17.0-node
  12. Affected versionversion=v0.18.0-rc1-scratch <v1.17.0-scratch

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Gleam · Gleamversion=0.18.0-rc1 <1.17.0; version=ed7aec0484f10d60978b63788c8a6497590855ab <690ca069817bee5f77a28fc3e360627c1da19291; version=v0.18.0-rc1-elixir-alpine <v1.17.0-elixir-alpine; version=v0.18.0-rc1-elixir-slim <v1.17.0-elixir-slim; version=v0.18.0-rc1-elixir <v1.17.0-elixir; version=v0.18.0-rc1-erlang-alpine <v1.17.0-erlang-alpine; version=v0.18.0-rc1-erlang-slim <v1.17.0-erlang-slim; version=v0.18.0-rc1-erlang <v1.17.0-erlang; version=v0.18.0-rc1-node-alpine <v1.17.0-node-alpine; version=v0.18.0-rc1-node-slim <v1.17.0-node-slim; version=v0.18.0-rc1-node <v1.17.0-node; version=v0.18.0-rc1-scratch <v1.17.0-scratch

Published CVSS scores

5.6GitHub Security AdvisoryCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1204.002Malicious File
T1485Data Destruction

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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