CVE-2020-4068: In APNSwift 1.0.0, calling APNSwiftSigner.sign(digest:) is likely to result in a heap buffer overflow

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MEDIUM 6.3DOWNGRADE

CVE-2020-4068 is a medium-severity flaw (CVSS 6.3) affecting apnswift. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In APNSwift 1.0.0, calling APNSwiftSigner.sign(digest:) is likely to result in a heap buffer overflow. This has been fixed in 1.0.1.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-122
Published	2020-06-22
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: apnswift project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-06-22 16:15 UTCPublished CVE record published
2026-06-17 03:19 UTCUpdated Record last modified

apnswift project apnswift DOWNGRADE

Affected: 1.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy apnswift || rpm -q apnswift || apnswift --version

2. No fixed release: DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison apnswift sudo apt install apnswift=<VERSION_BEFORE_1.0.0> sudo apt-mark hold apnswift

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list apnswift sudo dnf downgrade apnswift-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add apnswift

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-4068?

apnswift: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-4068 being exploited?

CVE-2020-4068 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-4068 affect?

CVE-2020-4068 affects apnswift. Severity is medium (CVSS 6.3). In APNSwift 1.0.0, calling APNSwiftSigner.sign(digest:) is likely to result in a heap buffer overflow. This has been fixed in 1.0.1.

How urgent is CVE-2020-4068?

Priority 40/100. No elevated risk signals yet.

References

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