# CVE-2026-104861: probe-image-size: Quadratic-time Denial of Service in the SVG Parser

> An attacker can cause a denial of service by sending crafted SVG data that triggers quadratic-time regex scanning, blocking the Node.js event loop.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Oct 2026
- **Updated:** 2 Oct 2026
- **Also known as:** CLSA-2026-1791028047, CLSA-2026-1792489910, GHSA-gjj5-9665-rwrc, MINI-wj6p-gj4m-pwxp, MINI-wmq9-crw2-6xvg

## What is CVE-2026-104861?

CVE-2026-104861 is a high-severity denial of service vulnerability in nodeca probe-image-size, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

probe-image-size gets image dimensions without downloading the entire file. Prior to 7.4.0, lib/parse_sync/svg.js and lib/parse_stream/svg.js use the searching regular expression /<[-_.:a-zA-Z0-9][^>]*>/, which repeatedly scans to the end of input when attacker-controlled data contains many less-than characters without a closing greater-than character. The synchronous parser converts and scans the full supplied buffer without an input cap, while the streaming parser reparses the complete accumulated SVG prefix for every received chunk. The probe.sync(), probe(stream), and probe(url) entry points can therefore block the Node.js event loop at full CPU, and attacker-controlled chunking can amplify the streaming cost. This issue is fixed in version 7.4.0.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-104861?

2 open source packages ship an affected version, including probe-image-size.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `probe-image-size` | npm | All versions | 7.4.0 |
| `probe-image-size` | npm | All versions | 7.4.0 |

## How do I fix CVE-2026-104861?

Upgrade probe-image-size to 7.4.0 or later.

## Is CVE-2026-104861 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104861 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104861 and fix it if it is affected.

What it is: CVE-2026-104861 is a high-severity denial of service vulnerability in nodeca probe-image-size, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104861 exists.

Affected packages and fixed versions:
- probe-image-size (npm): affected all versions; fixed in 7.4.0
- probe-image-size (npm): affected all versions; fixed in 7.4.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-104861/ (Markdown: https://insights.sbomify.com/CVE-2026-104861/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104861
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104861
- OSV: https://osv.dev/vulnerability/CVE-2026-104861

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104861/
Summaries are generated and may contain mistakes; the official description above is the record.