Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Checkout DevGuardView on GitHub
Search

GHSA-f4f9-627c-jh33

HighCVSS 7.6 / 10
Published Apr 8, 2026·Last modified May 26, 2026
Affected Components(0)

No affected components available

Description

Summary

objects/aVideoEncoderReceiveImage.json.php allowed an authenticated uploader to fetch attacker-controlled same-origin /videos/... URLs, bypass traversal scrubbing, and expose server-local files through the GIF poster storage path.

The vulnerable GIF branch could be abused to read local files such as /etc/passwd or application source files and republish those bytes through a normal public GIF media URL.

Details

The vulnerable chain was:

  1. objects/aVideoEncoderReceiveImage.json.php accepted attacker-controlled downloadURL_gifimage
  2. traversal scrubbing used str_replace('../', '', ...), which was bypassable with overlapping input such as ....//
  3. same-origin /videos/... URLs were accepted
  4. url_get_contents() and try_get_contents_from_local() resolved the request into a local filesystem read
  5. the fetched bytes were written into the GIF destination
  6. invalid GIF cleanup used the wrong variable, so the non-image payload remained on disk

This made the GIF poster path a local file disclosure primitive with public retrieval.

Proof of concept

  1. Log in as an uploader and create an owned video row through the normal encoder flow.
  2. Send:
POST /objects/aVideoEncoderReceiveImage.json.php
downloadURL_gifimage=https://localhost/videos/....//....//....//....//....//....//etc/passwd
  1. Query:
GET /objects/videos.json.php?showAll=1
  1. Recover the generated GIF URL from videosURL.gif.url.
  2. Download that GIF URL.
  3. Observe that the body matches the target local file, such as /etc/passwd, byte-for-byte.

Impact

An authenticated uploader can read server-local files and republish them through a public GIF media URL by supplying a crafted same-origin /videos/... path to downloadURL_gifimage. Because traversal scrubbing was bypassable and the fetched bytes were written to the GIF destination without effective invalid-image cleanup, successful exploitation allows disclosure of files such as /etc/passwd, readable application source code, or deployment-specific configuration accessible to the application.

Recommended fix

  • Reject any remote image URL whose decoded path contains traversal markers
  • Do not allow attacker-controlled same-origin /videos/... fetches to resolve into local file reads
  • Constrain any local shortcut path handling with realpath() and strict base-directory allowlists
  • Validate GIF content before saving it into public media storage
  • Ensure invalid-image cleanup checks the correct destination path
Risk Scores
Base Score
7.6

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a low impact on the integrity of the data. There is a low impact on the availability of the system.

Threat Intelligence
7.0

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.72%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

High severity
Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard