Unauthorized Access in Pixelfed by Geo-Chen
CVE-2026-86178

5.3MEDIUM

Key Information:

Vendor

Pixelfed

Status
Pixelfed
Vendor
CVE Published:
5 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-86178?

Pixelfed, up to version 0.12.9, contains a flaw in its StoryComposeController, where it does not validate follower status for its react and comment endpoints. This oversight allows authenticated users to access follower-only stories without necessary permissions. By exploiting this vulnerability, attackers can enumerate story IDs sequentially, enabling them to submit reactions or comments that facilitate unauthorized retrieval of story media URLs and author information, even if they do not follow the respective accounts.

Affected Version(s)

pixelfed 0 <= 0.12.9

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-86178 - Proof of Concept

References

https://github.com/geo-chen/oss/blob/main/Pixelfed.md
third-party-advisoryexploit
https://github.com/pixelfed/pixelfed/blob/v0.12.9/app/Htt...
technical-description
https://github.com/pixelfed/pixelfed/blob/v0.12.9/app/Htt...
technical-description

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

George Chen
.