Cyber Resilience

CVE-2023-36460

Path Traversal in Joinmastodon Mastodon 3.5.0 – 3.5.9

Published
06 July 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 9.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.40 99th percentile
Risk Priority 87 floored blend · peak EPSS

Summary

CVE-2023-36460 is a critical-severity Path Traversal (CWE-22) vulnerability in Joinmastodon Mastodon. Its CVSS base score is 9.9 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Mastodon, an open-source ActivityPub-based social network server, contains a path traversal vulnerability (CWE-22) in its media processing code. The flaw affects versions 3.5.0 through 3.5.8, 4.0.0 through 4.0.4, and 4.1.0 through 4.1.2; specially crafted media files can cause the server to write arbitrary files to any location on the filesystem accessible to the Mastodon process.

An attacker with a low-privileged account can upload the malicious media over the network and achieve arbitrary file creation or overwrite. This grants the ability to perform denial-of-service attacks by corrupting critical files and, in many deployments, to obtain remote code execution by placing attacker-controlled content in executable locations or configuration paths.

Patches addressing the issue were released in Mastodon 3.5.9, 4.0.5, and 4.1.3; the corresponding fix is tracked in commit dc8f1fbd976ae544720a4e07120d9a91b2722440. Administrators should upgrade to one of the patched versions and verify that media upload handling is restricted to trusted users until the update is applied. The EPSS score has remained flat at 0.4485 with no observed rise after disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 3.5.0 and prior to versions 3.5.9, 4.0.5, and 4.1.3, attackers using carefully crafted media files can cause Mastodon's media processing code to create arbitrary files at…

more

any location. This allows attackers to create and overwrite any file Mastodon has access to, allowing Denial of Service and arbitrary Remote Code Execution. Versions 3.5.9, 4.0.5, and 4.1.3 contain a patch for this issue.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-21048Shared CWE-22
CVE-2026-23939Shared CWE-22
CVE-2024-7145Shared CWE-22
CVE-2023-42225Shared CWE-22
CVE-2024-33109Shared CWE-22
CVE-2023-35016Shared CWE-22
CVE-2025-10723Shared CWE-22
CVE-2023-1163Shared CWE-22
CVE-2024-43996Shared CWE-22
CVE-2024-48510Shared CWE-22

Affected Assets

joinmastodon
mastodon
3.5.0 — 3.5.9 · 4.0.0 — 4.0.5 · 4.1.0 — 4.1.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-22

Validates pathnames and filenames to prevent traversal outside intended directories.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

PR.AA-05 none match
prevents

PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development catches path traversal via static/dynamic analysis.

prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

prevents

Application security requirements include rules for safe file handling and canonicalization.

prevents

Secure architecture principles require least-privilege file access and directory isolation.

prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

mitigates

Information access restriction limits which files an application may read or write.

References