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Fencer Vulns
high 8.0

CVE-2023-22726 json

Unrestricted file upload leading to privilege escalation in act

published 2023-01-20 3 y ago modified 2026-09-10 1 mo ago also GHSA-pc99-qmg4-rcff , GO-2023-1504 , EUVD-2023-0514

cvss
8.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

act is a project which allows for local running of github actions. The artifact server that stores artifacts from Github Action runs does not sanitize path inputs. This allows an attacker to download and overwrite arbitrary files on the host from a Github Action. This issue may lead to privilege escalation. The /upload endpoint is vulnerable to path traversal as filepath is user controlled, and ultimately flows into os.Mkdir and os.Open. The /artifact endpoint is vulnerable to path traversal as the path is variable is user controlled, and the specified file is ultimately returned by the server. This has been addressed in version 0.2.40. Users are advised to upgrade. Users unable to upgrade may, during implementation of Open and OpenAtEnd for FS, ensure to use ValidPath() to check against path traversal or clean the user-provided paths manually.

Patch / fix

  • go github.com/nektos/act 0.2.40
  • act_project act 0.2.40

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
19 mo ago

Exploit prediction

1.29% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nektos/act/security/advisories/GHSA-pc99-qmg4-rcff referenced PoC, tagged "exploit" by a source, unverified
  • securitylab.github.com https://securitylab.github.com/advisories/GHSL-2023-004_act/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/nektos/act
<0.2.40
0.2.40

Affected products

  • nektos act

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.