# CVE-2018-25026: actix-web memory corruption via unsound Send trait implementation

Source: https://junglewise.ai/threats/cve-2018-25026-actix-web-memory-corruption-via-unsound-send-trait-implementation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-01-06. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2018-25026 · Severity: critical · CVSS 9.8 · Published 2022-01-06

actix-web is a popular framework for building web applications in the Rust programming language. A vulnerability was identified where the software incorrectly handles data across different processing threads, which can lead to memory corruption. This could allow a remote attacker to crash the web server or potentially execute unauthorized code, impacting the availability and security of the hosted application.

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

## Quick answers

**Is CVE-2018-25026 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2018-25026 being exploited in the wild.

**How severe is CVE-2018-25026?** Critical severity, with a CVSS score of 9.8, published 6 January 2022.

**Which products and versions are affected?** actix-web (crates.io) < 0.7.19.

**Is there a fix for CVE-2018-25026?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2018-25026 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2018-25026?** Check whether you run 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.

## Technical details

The actix-web crate prior to version 0.7.19 contains multiple memory safety issues stemming from unsound use of 'unsafe' blocks. Specifically, the library incorrectly applied the 'Send' marker trait to objects that are not thread-safe, allowing them to be transferred across thread boundaries. This violation of Rust's memory safety guarantees can result in out-of-bounds writes, use-after-free conditions, and general memory corruption. An attacker can exploit these flaws over the network without authentication to cause a denial of service or achieve remote code execution. The issues were addressed through a significant refactoring of the codebase to remove unsound unsafe operations.

## Affected products

- actix actix-web < 0.7.19

## Identifiers

- CVE-2018-25026
- GHSA-7x36-h62w-vw65

## Timeline

- 2018-06-08: disclosed: Initial report of unsound unsafe usage in actix-web issue tracker
- 2021-12-27: advisory: NVD published CVE-2018-25026
- 2022-01-06: advisory: GitHub Advisory GHSA-7x36-h62w-vw65 published

## References

- [https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/actix-web/RUSTSEC-2018-0019.md](https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/actix-web/RUSTSEC-2018-0019.md)
- [https://rustsec.org/advisories/RUSTSEC-2018-0019.html](https://rustsec.org/advisories/RUSTSEC-2018-0019.html)
- [https://github.com/actix/actix-web/issues/289](https://github.com/actix/actix-web/issues/289)

## Related threats

- [actix-web denial of service via compressed request bodies](https://junglewise.ai/threats/rustsec-2026-0447-compressed-request-bodies-can-exhaust-memory-before-b7c4ea38)
- [actix-web memory corruption via unsound reference coercion](https://junglewise.ai/threats/cve-2018-25024-actix-web-memory-corruption-via-unsound-reference-coercion)
- [Actix actix-web out-of-bounds write via unsound string lifetimes](https://junglewise.ai/threats/cve-2018-25025-actix-actix-web-out-of-bounds-write-via-unsound-string-lifetimes)