CVE-2021-27376Network attack vector

Invalid memory access via layout-unsafe socket casts

Published Feb 18, 2021 · Updated Aug 3, 2024

Memory-safety flaw in the nb-connect crate before 1.0.3 allows remote attackers to trigger invalid memory access during socket setup. Addr::new directly casts Rust SocketAddrV4 or SocketAddrV6 pointers to the system sockaddr representation and copies bytes using the Rust type's size despite no guaranteed layout compatibility. The condition arises when the standard library uses a different address layout, exposing the host process to silent invalid reads and memory corruption.

CVSS severity9.8
Critical
EPSS probability1.45%
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 the nb-connect crate before 1.0.3 allows remote attackers to trigger invalid memory access during socket setup. Addr::new directly casts Rust SocketAddrV4 or SocketAddrV6 pointers to the system sockaddr representation and copies bytes using the Rust type's size despite no guaranteed layout compatibility. The condition arises when the standard library uses a different address layout, exposing the host process to silent invalid reads and memory corruption.

The record

CVE
CVE-2021-27376
Published
Feb 18, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 18, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8RustSec Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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