- Exploited
- No known exploitation
- Fix
- Fixed in 3.20.3
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 3.20.3.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 10/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Actix Web's actix-http component, when built with the `compress-brotli` feature (enabled by default in Actix Web), can be made to allocate about 1 GiB of memory from a crafted, Brotli-compressed request body of roughly 850 bytes before the configured size limit applies. Concurrent requests of this kind can exhaust process or host memory, causing a denial of service.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
With the compress-brotli feature enabled, the decoder accepts the non-standard large-window Brotli format. A crafted stream can cause its internal buffer to grow to about 1 GiB before the decoded output reaches the configured size limit. An 850-byte request can cause this allocation, and concurrent requests can exhaust process or host memory.
Actix Web enables Brotli support by default. Applications that read request bodies through Bytes, String, Json, or Form can be affected even when extractor size limits are configured. The allocation occurs before the handler runs, so authentication performed in the handler does not prevent it.
Upgrade to actix-http 3.20.3 or later. As a workaround, reject requests with Content-Encoding: br at a reverse proxy or in middleware before body extraction, or disable the compress-brotli feature throughout the dependency graph.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach10/20Affects crates.io packages
- Severity?/10Unknown. No CVSS score or vendor rating
- No patch0/5No signal
What would change the score
- Would score about 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 32 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 3.20.3.
Timeline
- Advisory published
- Record last updated
- First seen by cve.now
Affected versions
- actix-httpcrates.io
From 0.0.0-0 · fixed in 3.20.3
Evidence 3
- Advisory
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about RUSTSEC-2026-0455
Is RUSTSEC-2026-0455 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by RUSTSEC-2026-0455?
actix-http (crates.io): from 0.0.0-0 before 3.20.3.Source: cve.now feed data
How do I fix RUSTSEC-2026-0455?
Upgrade to a fixed version: 3.20.3.Source: cve.now feed data