What is CVE-2019-15551?

CVE-2019-15551 is a critical-severity vulnerability in Servo Smallvec, classified under Double Free. CVSS score: 9.8/10. Published 2019-08-26.

How severe is CVE-2019-15551?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2019-15551 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Double Free in Servo Smallvec

CVE-2019-15551

An issue was discovered in the smallvec crate before 0.6.10 for Rust. There is a double free for certain grow attempts with the current capacity.

Vulnerability class: Double Free

Published 2019-08-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.019 (78.4th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 78th percentile — 78.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.019 · newest: 0.019 · change: 0.000

Affected products

Servo Smallvec

Weakness classification (CWE)

CWE-415 — Double Free

Public proof-of-concept exploits

Artisan-Lab/Rust-memory-safety-bugs

References

rustsec.org/advisories/RUSTSEC-2019-0009.html (Third Party Advisory)
github.com/servo/rust-smallvec/issues/148 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2019-15551?: CVE-2019-15551 is a critical-severity vulnerability in Servo Smallvec, classified under Double Free. CVSS score: 9.8/10. Published 2019-08-26.
How severe is CVE-2019-15551?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2019-15551 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.