CVE-2018-20991
Double free in smallvec
An issue was discovered in the smallvec crate before 0.6.3 for Rust. The Iterator implementation mishandles destructors, leading to a double free.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the smallvec crate before 0.6.3 for Rust. The Iterator implementation mishandles destructors, leading to a double free.
- Record
CVE-2018-20991- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-415
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the smallvec crate before 0.6.3 for Rust. The Iterator implementation mishandles destructors, leading to a double free.
- Record
CVE-2018-20991- Updated
- 2026-11-02
EUVDEUVD-2021-1878 No score
An issue was discovered in the smallvec crate before 0.6.3 for Rust. The Iterator implementation mishandles destructors, leading to a double free.
- Record
EUVD-2021-1878- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-rxr4-x558-x7hw
Double free in smallvec
If an iterator passed to SmallVec::insert_many panicked in Iterator::next, destructors were run during unwinding while the vector was in an inconsistent state, possibly causing a double free (a destructor running on two copies of the same value).
This is fixed in smallvec 0.6.3 by ensuring that the vector's length is not updated to include moved items until they have been removed from their original positions. Items may now be leaked if Iterator::next panics, but they will not be dropped more than once.
- Record
GHSA-rxr4-x558-x7hw- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-415
- Updated
- 2026-11-02
OSV
An issue was discovered in the smallvec crate before 0.6.3 for Rust. The Iterator implementation mishandles destructors, leading to a double free.
- Record
CVE-2018-20991- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-rxr4-x558-x7hw
Double free in smallvec
If an iterator passed to SmallVec::insert_many panicked in Iterator::next, destructors were run during unwinding while the vector was in an inconsistent state, possibly causing a double free (a destructor running on two copies of the same value).
This is fixed in smallvec 0.6.3 by ensuring that the vector's length is not updated to include moved items until they have been removed from their original positions. Items may now be leaked if Iterator::next panics, but they will not be dropped more than once.
- Record
GHSA-rxr4-x558-x7hw- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-415
- Updated
- 2026-11-02
OSVRUSTSEC-2018-0003
Possible double free during unwinding in SmallVec::insert_many
If an iterator passed to SmallVec::insert_many panicked in Iterator::next,
destructors were run during unwinding while the vector was in an inconsistent
state, possibly causing a double free (a destructor running on two copies of
the same value).
This is fixed in smallvec 0.6.3 by ensuring that the vector's length is not
updated to include moved items until they have been removed from their
original positions. Items may now be leaked if Iterator::next panics, but
they will not be dropped more than once.
Thank you to @Vurich for reporting this bug.
- Record
RUSTSEC-2018-0003- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2018-20991
An issue was discovered in the smallvec crate before 0.6.3 for Rust. The Iterator implementation mishandles destructors, leading to a double free.
- Record
UBUNTU-CVE-2018-20991- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVSUSE-SU-2021:1310-1 No score
Security update for librsvg
This update for librsvg fixes the following issues:
- librsvg was updated to 2.42.9:
- Update dependent crates that had security vulnerabilities: smallvec to 0.6.14 - RUSTSEC-2018-0003 - CVE-2018-20991 (bsc#1148293) -the bundled version of the cssparser crate now builds correctly on Rust 1.43 (bsc#1181571).
- Record
SUSE-SU-2021:1310-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
smallveccrates.io |
0.3.2 up to 0.6.3 | 0.6.3 |
smallveccrates.io |
0.3.2 up to 0.3.4, 0.4.0-0 up to 0.4.5, 0.5.0-0 up to 0.5.1, 0.6.0-0 up to 0.6.3 | 0.3.40.4.50.5.10.6.3 |
librsvgSUSE:Linux Enterprise Module for Package Hub 15 SP2 |
before 2.42.9-3.6.1 | 2.42.9-3.6.1 |
rust-smallvecUbuntu:20.04:LTS |
All versions, plus listed versions 0.6.10-11.1.0-1 |
None known |
rust-smallvecUbuntu:22.04:LTS |
All versions, plus listed versions 1.4.2-21.7.0-1 |
None known |
rust-smallvecUbuntu:24.04:LTS |
All versions, plus listed versions 1.11.0-11.11.2-1 |
None known |
rust-smallvecUbuntu:25.10 |
All versions, plus listed versions 1.13.2-1 |
None known |
rust-smallvecUbuntu:26.10 |
All versions, plus listed versions 1.15.1-11.15.2-1 |
None known |
rust-smallvecUbuntu:26.04:LTS |
All versions, plus listed versions 1.13.2-11.15.1-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-20991 is a critical vulnerability (CVSS 9.8) in Servo Smallvec, published July 19, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.85%, the 79th percentile. Fixed in smallvec 0.6.3.