Improper Input Validation in once_cell

published 2019-09-01 7 y ago modified 2026-06-17 4 mo ago also GHSA-7j44-fv4x-79g9 , RUSTSEC-2019-0017 , EUVD-2021-1622

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.6%; EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits: 0; none known

An issue was discovered in the once_cell crate before 1.0.1 for Rust. There is a panic during initialization of Lazy.

Patch / fix

fixed in 2 links 2

crates.io once_cell 1.0.1
once_cell_project once_cell 1.0.1

github.com/matklad/once_cell@afcca95 commit
github.com/matklad/once_cell#47 pull request

Exploit prediction

1.58% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
crates.io	once_cell	>=0.2.5, <1.0.1	1.0.1

Classification

Weakness

CWE-20 Improper Input Validation

References

github.com /matklad/once_cell/pull/47
web
github.com /matklad/once_cell/commit/afcca95a05240ebd931ab20998c946f77ef1e284
web
rustsec.org /advisories/RUSTSEC-2019-0017.html
web, third-party-advisory, advisory
github.com /matklad/once_cell/issues/46
web, third-party-advisory, report
nvd.nist.gov /vuln/detail/CVE-2019-16141
advisory
github.com /matklad/once_cell
package
crates.io /crates/once_cell
package

Sources

Fencer Vulns 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.

Summary