CVE-2021-40526: Incorrect calculation of buffer size vulnerability in Peleton TTR01 up to and including PTV55G allows a remote

Q: How do I fix CVE-2021-40526?

ttr01 firmware: upgrade to newer than ptv55g. Exact commands for each OS are on this page.

Q: Is CVE-2021-40526 being exploited?

CVE-2021-40526 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-40526 affect?

CVE-2021-40526 affects ttr01 firmware. Severity is medium (CVSS 4.8). Incorrect calculation of buffer size vulnerability in Peleton TTR01 up to and including PTV55G allows a remote attacker to trigger a Denial of Service attack through the GymKit daemon process by exploiting a heap overflow in the network ser

Q: How urgent is CVE-2021-40526?

Priority 37/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 4.8REMOTEUPGRADE

CVE-2021-40526 is a medium-severity flaw (CVSS 4.8) affecting ttr01 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Incorrect calculation of buffer size vulnerability in Peleton TTR01 up to and including PTV55G allows a remote attacker to trigger a Denial of Service attack through the GymKit daemon process by exploiting a heap overflow in the network server handling the Apple GymKit communication. This can lead to an Apple MFI device not being able to authenticate with the Peleton Bike

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Weakness	CWE-131
Published	2021-10-25
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: onepeloton

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

Am I affected?

Timeline

2021-10-25 11:15 UTCPublished CVE record published
2026-06-17 04:07 UTCUpdated Record last modified

onepeloton ttr01 firmware UPGRADE

Affected: <= ptv55g

Fixed in: newer than ptv55g

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-40526?

ttr01 firmware: upgrade to newer than ptv55g. Exact commands for each OS are on this page.

Is CVE-2021-40526 being exploited?

CVE-2021-40526 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-2021-40526 affect?

CVE-2021-40526 affects ttr01 firmware. Severity is medium (CVSS 4.8). Incorrect calculation of buffer size vulnerability in Peleton TTR01 up to and including PTV55G allows a remote attacker to trigger a Denial of Service attack through the GymKit daemon process by exploiting a heap overflow in the network ser

How urgent is CVE-2021-40526?

Priority 37/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-33887 MEDIUM 6.8 UPGRADE Insufficient verification of data authenticity in Peloton TTR01 up to and including PTV55G allows an attacker

References

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