CVE-2020-36317Public exploitNetwork attack vector

Memory corruption via panic-unsafe String retention

Published Apr 11, 2021 · Updated Aug 4, 2024

Memory corruption in the Rust standard library 1.26.0 through 1.48.0 allows attackers to violate UTF-8 invariants via String::retain. String::retain temporarily exposes a partially compacted buffer and fails to restore a valid length when its predicate closure panics, leaving non-UTF-8 bytes in a safe String. Exploitation requires code that supplies a panicking closure and catches the unwind; later String APIs can then trigger memory-safety violations, including out-of-bounds writes.

CVSS severity7.5
High
EPSS probability1.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in the Rust standard library 1.26.0 through 1.48.0 allows attackers to violate UTF-8 invariants via String::retain. String::retain temporarily exposes a partially compacted buffer and fails to restore a valid length when its predicate closure panics, leaving non-UTF-8 bytes in a safe String. Exploitation requires code that supplies a panicking closure and catches the unwind; later String APIs can then trigger memory-safety violations, including out-of-bounds writes.

The record

CVE
CVE-2020-36317
Published
Apr 11, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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