# RUSTSEC-2026-0174: `Authorization::value` and `WwwAuthenticate::value` can violate ASCII invariants

> Safe code can construct HTTP headers with non-ASCII characters, violating internal invariants and potentially causing undefined behavior in the unmaintained http-types crate.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Mar 2026

## What is RUSTSEC-2026-0174?

RUSTSEC-2026-0174 is a vulnerability in http-types, published on 11 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

`Authorization::value` uses `HeaderValue::value` with the claim
that the internal string is ASCII, but `Authorization::new` and
`Authorization::set_credentials` accept arbitrary `String` credentials without
validation. As a result, safe code can construct a header value containing
non-ASCII UTF-8 while the implementation assumes ASCII.

`WwwAuthenticate::new` and `WwwAuthenticate::set_realm` similarly accepts arbitrary `String` input, so `WwwAuthenticate::value` can also produce a header value that violates the crate’s documented ASCII invariants. 

This issue has not been confirmed as Undefined Behavior, but the unsafe
justification in `Authorization::value` and `WwwAuthenticate::value` appears incorrect and can produce values outside the expected ASCII-only constraints.

The http-types crate is unmaintained and the issue is unlikely to be fixed.

## Which versions are affected by RUSTSEC-2026-0174?

1 open source package ship an affected version, including http-types.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `http-types` | crates.io | From 0.0.0-0 | None |

## How do I fix RUSTSEC-2026-0174?

No fix has been published for RUSTSEC-2026-0174 yet. Limit exposure of the affected software until one is available.

## Is RUSTSEC-2026-0174 being exploited?

There is no known exploitation of RUSTSEC-2026-0174 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0174 and fix it if it is affected.

What it is: RUSTSEC-2026-0174 is a vulnerability in http-types, published on 11 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of RUSTSEC-2026-0174 in the wild and no public exploit code.

Affected packages and fixed versions:
- http-types (crates.io): affected from 0.0.0-0; no fix listed

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/RUSTSEC-2026-0174/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0174/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0174

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0174/
Summaries are generated and may contain mistakes; the official description above is the record.