# actix-web denial of service via compressed request bodies

Source: https://junglewise.ai/threats/rustsec-2026-0447-compressed-request-bodies-can-exhaust-memory-before-b7c4ea38  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-06. Updated: 2026-11-07  
License: CC BY 4.0 with a link back

Severity: info · Published 2026-11-06

actix-web is a web framework for Rust applications. A flaw in how the framework handles compressed HTTP request bodies allows attackers to send small compressed payloads that expand to massive sizes in memory, causing the application to run out of memory or CPU and become unavailable.

Technologies: [Actix-Http](https://junglewise.ai/threats/technologies/actix-actix-http), [actix-web (crates.io)](https://junglewise.ai/threats/technologies/actix-web). Vendors: [Actix](https://junglewise.ai/threats/vendors/actix), [crates.io](https://junglewise.ai/threats/vendors/crates-io).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Informational severity, published 6 November 2026.

**Which products and versions are affected?** Actix-Http before 3.20.1; Actix-Web before 4.18.2; actix-web (crates.io) SEMVER:introduced=0.0.0-0,fixed=4.18.2.

**Is there a fix for This vulnerability?** Yes. actix-web (crates.io): upgrade to 4.18.2 or later. Until then: Reject compressed request bodies at a reverse proxy or in middleware before body extraction. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run Actix-Http, Actix-Web or actix-web (crates.io) 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

- actix-web (crates.io): upgrade to 4.18.2 or later

  ```sh
  cargo update -p actix-web
  ```


Reject compressed request bodies at a reverse proxy or in middleware before body extraction.

## Technical details

The body extractors in actix-web do not enforce their size limits on the decompression layer, allowing a remotely-sourced small compressed request to decompress to an arbitrarily large allocation before the extractor's size checks reject it. An unauthenticated remote attacker can exploit this to exhaust memory or CPU resources and cause denial of service, provided the application has compression features enabled and processes compressed request bodies.

## Affected products

- actix actix-web before 4.18.2
- actix actix-http before 3.20.1

## Identifiers

- GHSA-qph8-7859-gq2f
- RUSTSEC-2026-0447
- RUSTSEC-2026-0448

## Timeline

- 2026-11-06: disclosed

## References

- [https://crates.io/crates/actix-web](https://crates.io/crates/actix-web)
- [https://rustsec.org/advisories/RUSTSEC-2026-0447.html](https://rustsec.org/advisories/RUSTSEC-2026-0447.html)

## Related threats

- [actix-http request smuggling through malformed chunked trailers](https://junglewise.ai/threats/rustsec-2026-0446-request-smuggling-through-malformed-chunked-request-5ce6bfaf)
- [actix-http memory exhaustion via large-window Brotli](https://junglewise.ai/threats/rustsec-2026-0455-large-window-brotli-bodies-bypass-decompression-8b64dc69)
- [actix-http unbounded decompression denial of service](https://junglewise.ai/threats/rustsec-2026-0448-unbounded-decompression-can-exhaust-memory-and-cpu-f56d9644)
- [actix-web memory corruption via unsound reference coercion](https://junglewise.ai/threats/cve-2018-25024-actix-web-memory-corruption-via-unsound-reference-coercion)
- [actix-web memory corruption via unsound Send trait implementation](https://junglewise.ai/threats/cve-2018-25026-actix-web-memory-corruption-via-unsound-send-trait-implementation)