CVE-2020-25574 — http
HIGHCVE-2020-25574 is a high-severity (CVSS 7.5) CWE-190 vulnerability in http. 1 public exploit reference exists, so weaponization risk is real. A fix is available for http — see the affected versions and patch details below.
Integer Overflow/Infinite Loop in the http crate
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-25574 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
httpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
HeaderMap::reserve() used usize::next_power_of_two() to calculate the increased capacity. However, next_power_of_two() silently overflows to 0 if given a sufficiently large number in release mode.
If the map was not empty when the overflow happens, the library will invoke self.grow(0) and start infinite probing. This allows an attacker who controls the argument to reserve() to cause a potential denial of service (DoS).
The flaw was corrected in 0.1.20 release of http crate.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | http | all versions | 0.1.20cargo update -p http --precise 0.1.20 |
Affected Products
httphyperResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update http to 0.1.20 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-25574 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Frequently Asked Questions
Is CVE-2020-25574 in your dependencies?
Find it across crates.io, including transitive dependencies.