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Fencer Vulns
high 7.5

CVE-2020-36317 json

In the standard library in Rust before 1.49.0, String::retain() function has a panic safety problem.

published 2021-04-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-23859

cvss
7.5
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

In the standard library in Rust before 1.49.0, String::retain() function has a panic safety problem. It allows creation of a non-UTF-8 Rust string when the provided closure panics. This bug could result in a memory safety violation when other string APIs assume that UTF-8 encoding is used on the same string.

Patch / fix

  • rust-lang rust 1.49.0
  • rustc Debian 14, Debian 13, Debian 12 1.53.0+dfsg1-1

debian advisories DEBIAN-CVE-2020-36317

  • rustc Ubuntu 20.04 LTS 1.51.0+dfsg1+llvm-1~exp3ubuntu1~20.04.2

ubuntu advisories UBUNTU-CVE-2020-36317

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rls RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • rust RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • cargo RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • clippy RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • rustfmt RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • rust-gdb RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • rust-src RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08
  • rust-lldb RHEL 8 1.49.0-1.module+el8.4.0+9446+1a463e08

red hat advisories RHSA-2021:1935RHSA-2021:2243

  • rust Rocky Linux 8 1.49.0-1.module+el8.4.0+416+259a129a
  • rust-toolset Rocky Linux 8 1.49.0-1.module+el8.4.0+416+259a129a

rocky linux advisories RLSA-2021:1935

  • rust Arch Linux 1:1.49.0-1

arch linux advisories AVG-1804

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-36317 updated cvss 5.3

rust: memory safety violation in String::retain()

  • Red Hat Developer Tools for Red Hat Enterprise Linux Server (v. 7) rust-toolset-1.49 1.49.0-1.el7_9, rust-toolset-1.49-rls 1.49.0-1.el7_9, rust-toolset-1.49-rust 1.49.0-1.el7_9, rust-toolset-1.49-build 1.49.0-1.el7_9, rust-toolset-1.49-cargo 1.49.0-1.el7_9, rust-toolset-1.49-clippy 1.49.0-1.el7_9, +7 more Red Hat Developer Tools for Red Hat Enterprise Linux Workstation (v. 7) rust-toolset-1.49 1.49.0-1.el7_9, rust-toolset-1.49-rls 1.49.0-1.el7_9, rust-toolset-1.49-rust 1.49.0-1.el7_9, rust-toolset-1.49-build 1.49.0-1.el7_9, rust-toolset-1.49-cargo 1.49.0-1.el7_9, rust-toolset-1.49-clippy 1.49.0-1.el7_9, +7 more
    fixed: vendor fix RHSA-2021:2243
  • Red Hat Enterprise Linux AppStream (v. 8) rls 1.49.0-1.module+el8.4.0+9446+1a463e08, rust 1.49.0-1.module+el8.4.0+9446+1a463e08, cargo 1.49.0-1.module+el8.4.0+9446+1a463e08, clippy 1.49.0-1.module+el8.4.0+9446+1a463e08, rustfmt 1.49.0-1.module+el8.4.0+9446+1a463e08, rust-gdb 1.49.0-1.module+el8.4.0+9446+1a463e08, +5 more
    fixed: vendor fix RHSA-2021:1935
  • Red Hat Enterprise Linux 9 rust, cargo, clippy, rustfmt, rust-gdb, rust-src, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.50% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/rust-lang/rust/issues/78498 referenced PoC, tagged "exploit" by a source, unverified

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

Classification

Weakness

References

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.