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VulnerabilityPublished Updated

CVE-2026-43965: Gleam · Path Traversal

Affects GleamSource CVE Database V5

0
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Public exploit available · CVSS 5.6 Medium : upgrade to 1.17.0 as a priority.

Data as of 10 Nov 2026, 19:35 UTC

CVSS 4.0 base score
5.6Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (EEF)CVSS 4.05.6
CISA SSVC
Exploitation
Proof of concept is public or traded
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-06-02.

Patch
Available – fixed in 1.17.0, v1.17.0-scratch, v1.17.0-node-slim +9
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 2 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    CISA SSVC: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by Erlang Ecosystem Foundation

    , 29 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. CISA SSVC assessment

    proof of concept public

    , 1 hour after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
GleamgleamAffected
  • >=0.18.0-rc1 <1.17.0
Fixed in
  • 1.17.0
Gleamgleam-lang/gleamAffected
  • >=0.18.0-rc1-elixir <1.17.0-elixir
  • >=0.18.0-rc1-erlang <1.17.0-erlang
  • >=0.18.0-rc1-node <1.17.0-node
  • >=0.18.0-rc1-node-slim <1.17.0-node-slim
  • >=0.18.0-rc1-elixir-slim <1.17.0-elixir-slim
  • >=0.18.0-rc1-erlang-slim <1.17.0-erlang-slim
  • >=0.18.0-rc1-erlang-alpine <1.17.0-erlang-alpine
  • >=0.18.0-rc1-elixir-alpine <1.17.0-elixir-alpine
  • >=0.18.0-rc1-node-alpine <1.17.0-node-alpine
  • >=0.18.0-rc1-scratch <1.17.0-scratch
Fixed in
  • v1.17.0-scratch
  • v1.17.0-node-slim
  • v1.17.0-node-alpine
  • v1.17.0-node
  • v1.17.0-erlang-slim
  • v1.17.0-erlang-alpine
  • v1.17.0-erlang
  • v1.17.0-elixir-slim
  • v1.17.0-elixir-alpine
  • v1.17.0-elixir
Gleamgleam-lang/gleamAffected
  • ≥ ed7aec0484f10d60978b63788c8a6497590855ab, < 690ca069817bee5f77a28fc3e360627c1da19291
Fixed in
  • 690ca069817bee5f77a28fc3e360627c1da19291

CPE configurations (1)

  • cpe:2.3:a:gleam-lang:gleam:*:*:*:*:*:*:*:*

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Gleam version 1.17.0 and all its platform variants. Users should upgrade to version 1.17.0 or later to remediate this vulnerability. Until upgraded, avoid running 'gleam deps download' on untrusted projects or repositories that may contain malicious build/packages/packages.toml files.

Description

CVE-2026-43965 is a path traversal vulnerability in Gleam's dependency management system. It allows an attacker to cause arbitrary directory deletion on a victim's system by crafting malicious build/packages/packages.toml content. The vulnerability arises because package keys from this file are used without validation to construct filesystem paths, enabling traversal outside the intended directory. This affects Gleam versions from 0.18.0-rc1 up to but not including 1.17.0.

References

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