CVE-2021-28878Public exploit

Use-after-free via repeated unchecked Zip access

Published Apr 11, 2021 · Updated Aug 3, 2024

Memory-safety flaw in Rust standard library before 1.52.0 allows context-dependent attackers to trigger use-after-free via Zip iteration. The specialized ZipImpl repeats __iterator_get_unchecked for an index already processed by next_back() when later next() calls advance for side effects. Exploitation requires a program to combine next_back() and next() on a qualifying Zip iterator; duplicate unchecked access can create two mutable references to the same data and corrupt memory.

CVSS severity7.5
High
EPSS probability2.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-safety flaw in Rust standard library before 1.52.0 allows context-dependent attackers to trigger use-after-free via Zip iteration. The specialized ZipImpl repeats __iterator_get_unchecked for an index already processed by next_back() when later next() calls advance for side effects. Exploitation requires a program to combine next_back() and next() on a qualifying Zip iterator; duplicate unchecked access can create two mutable references to the same data and corrupt memory.

The record

CVE
CVE-2021-28878
Published
Apr 11, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer

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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