CVE-2026-28815: A remote attacker can supply a short X-Wing HPKE encapsulated key and trigger an out-of-bounds read in the C d

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HIGH 7.5REMOTEUPGRADE

CVE-2026-28815 is a high-severity flaw (CVSS 7.5) affecting swift-crypto. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A remote attacker can supply a short X-Wing HPKE encapsulated key and trigger an out-of-bounds read in the C decapsulation path, potentially causing a crash or memory disclosure depending on runtime protections. This issue is fixed in swift-crypto version 4.3.1.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 59%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-04-03
Last modified	2026-07-24

Publisher (CNA): Apple Inc. · Vendor: apple

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-03 03:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

apple swift-crypto UPGRADE

Affected: >= 4.0.0 and < 4.3.1

Fixed in: 4.3.1

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy swift-crypto || rpm -q swift-crypto || swift-crypto --version

2. UPGRADE to 4.3.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade swift-crypto

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade swift-crypto

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison swift-crypto sudo apt install swift-crypto=<VERSION_BEFORE_4.0.0> sudo apt-mark hold swift-crypto

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list swift-crypto sudo dnf downgrade swift-crypto-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add swift-crypto

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-2026-28815?

swift-crypto: upgrade to 4.3.1. Exact commands for each OS are on this page.

Is CVE-2026-28815 being exploited?

CVE-2026-28815 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-2026-28815 affect?

CVE-2026-28815 affects swift-crypto. Severity is high (CVSS 7.5). A remote attacker can supply a short X-Wing HPKE encapsulated key and trigger an out-of-bounds read in the C decapsulation path, potentially causing a crash or memory disclosure depending on runtime protections. This issue is fixed in swift

How urgent is CVE-2026-28815?

Priority 46/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Swift vulnerabilities

Related CVEs

CVE-2026-43823 HIGH 7.5 UPGRADE When initializing an RSA public key from DER or PEM bytes throws an error, the EVP_PKEY* is double-freed: firs

References

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