# CVE-2026-8814: ExifReader data amplification in PNG zTXt metadata decompression

Source: https://junglewise.ai/threats/cve-2026-8814-exifreader-data-amplification-in-png-ztxt-metadata-decompression  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-19. Updated: 2026-05-29  
License: CC BY 4.0 with a link back

CVE-2026-8814 · Severity: medium · CVSS 5.3 · Published 2026-05-19

ExifReader, a library used to read metadata from image files, is vulnerable to a denial-of-service attack. An attacker can provide a specially crafted image that, when processed, consumes excessive amounts of memory and CPU power. This can cause the application to slow down significantly or crash, potentially disrupting services that process user-uploaded images.

Technologies: [Mattias Wadstein ExifReader](https://junglewise.ai/threats/technologies/exifreader), [exifreader (npm)](https://junglewise.ai/threats/technologies/npm-exifreader). Vendors: [Mattias Wadstein](https://junglewise.ai/threats/vendors/mattias-wadstein), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-8814 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8814 being exploited in the wild.

**How severe is CVE-2026-8814?** Medium severity, with a CVSS score of 5.3, published 19 May 2026.

**Which products and versions are affected?** Mattias Wadstein ExifReader < 4.39.0, >= 4.20.0, < 4.39.0; exifreader (npm) SEMVER:introduced=4.20.0,fixed=4.39.0.

**Is there a fix for CVE-2026-8814?** Yes. exifreader (npm): upgrade to 4.39.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-8814 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-8814?** Check whether you run Mattias Wadstein ExifReader or exifreader (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- exifreader (npm): upgrade to 4.39.0 or later

  ```sh
  npm install exifreader@4.39.0
  ```


## Technical details

ExifReader (versions 4.20.0 to 4.38.1) contains a data amplification vulnerability (CWE-409) in its asynchronous decompression utility. When processing images via the asynchronous API (e.g., ExifReader.load), the library fails to bound the size of decompressed metadata blocks such as PNG zTXt/iCCP chunks or JPEG XL Brotli-compressed blocks. An attacker can exploit this by providing a small image file with highly compressed metadata that expands significantly upon decompression (e.g., 1000x expansion), leading to heap exhaustion and CPU spikes. The issue is fixed in version 4.39.0 by implementing incremental reading and a configurable decompression limit (defaulting to 128 MiB).

## Affected products

- mattiasw ExifReader >= 4.20.0, < 4.39.0

## Identifiers

- CVE-2026-8814
- GHSA-rr89-w3h9-m66j

## Timeline

- 2026-05-18: disclosed: Initial disclosure by reporter
- 2026-05-19: advisory: NVD publication date
- 2026-05-29: patched: GitHub Advisory reviewed and updated with patch information

## References

- [https://api.github.com/users/yuki-matsuhashi](https://api.github.com/users/yuki-matsuhashi)
- [https://github.com/yuki-matsuhashi](https://github.com/yuki-matsuhashi)
- [https://api.github.com/users/yuki-matsuhashi/gists%7B/gist_id%7D](https://api.github.com/users/yuki-matsuhashi/gists%7B/gist_id%7D)
- [https://api.github.com/users/yuki-matsuhashi/repos](https://api.github.com/users/yuki-matsuhashi/repos)
- [https://avatars.githubusercontent.com/u/250794953?v=4](https://avatars.githubusercontent.com/u/250794953?v=4)
- [https://api.github.com/users/yuki-matsuhashi/events%7B/privacy%7D](https://api.github.com/users/yuki-matsuhashi/events%7B/privacy%7D)

## Related threats

- [ExifReader denial of service via crafted HEIC/AVIF iloc box](https://junglewise.ai/threats/cve-2026-85715-exifreader-denial-of-service-via-crafted-heic-avif-iloc-box)
- [ExifReader denial of service via uncaught RangeError in ISO-BMFF parser](https://junglewise.ai/threats/cve-2026-53496-exifreader-denial-of-service-via-uncaught-rangeerror-in-iso-bmff)
- [ExifReader denial of service via memory exhaustion in ICC mluc tag parsing](https://junglewise.ai/threats/cve-2026-8813-exifreader-denial-of-service-via-memory-exhaustion-in-icc-mluc-tag)