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Fencer Intel
critical 9.8

CVE-2020-35926 json

Improper random number generation in nanorand

published 5y ago modified 4mo ago also GHSA-m9m5-cg5h-r582 , RUSTSEC-2020-0089 , EUVD-2021-1796

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

An issue was discovered in the nanorand crate before 0.5.1 for Rust. It caused any random number generator (even ChaCha) to return all zeroes because integer truncation was mishandled.

Patch / fix

  • crates.io nanorand 0.5.1
  • nanorand_project nanorand 0.5.1

Is CVE-2020-35926 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

1.53% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 5.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
OSV 3.1 5.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io nanorand
<0.5.1
>=0.0.0-0, <0.5.1
0.5.1

Classification

Weakness
  • CWE-330 Use of Insufficiently Random Values
  • CWE-681 Incorrect Conversion between Numeric Types
  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.