CVE-2020-4068Network attack vector

Heap over-read via unbounded BIO_puts

Published Jun 22, 2020 · Updated Aug 4, 2024

Heap-based buffer overflow in APNSwift 1.0.0 allows remote authenticated users to trigger an out-of-bounds heap read during signing. APNSwiftSigner.sign(digest:) passes its private-key ByteBuffer to BIO_puts without a terminating NUL, causing strlen to read beyond the 512-byte allocation. The condition is reached when an integrating application generates an ECDSA signature; public evidence demonstrates the over-read but not code execution.

CVSS severity6.3
Medium
EPSS probability1.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in APNSwift 1.0.0 allows remote authenticated users to trigger an out-of-bounds heap read during signing. APNSwiftSigner.sign(digest:) passes its private-key ByteBuffer to BIO_puts without a terminating NUL, causing strlen to read beyond the 512-byte allocation. The condition is reached when an integrating application generates an ECDSA signature; public evidence demonstrates the over-read but not code execution.

The record

CVE
CVE-2020-4068
Published
Jun 22, 2020
Updated
Aug 4, 2024
Vendor
Kyle Browning
Product
APNSwift
Classifications
CWE-122
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 22, 2020CVE 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?

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  1. Affected versionversion== 1.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Kyle Browning · APNSwiftversion== 1.0.0

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow

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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