CVE-2021-26834: A cross-site scripting (XSS) vulnerability exists in Znote 0.5.2

Routine

MEDIUM 5.4DOWNGRADE

CVE-2021-26834 is a medium-severity flaw (CVSS 5.4) affecting znote. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A cross-site scripting (XSS) vulnerability exists in Znote 0.5.2. An attacker can insert payloads, and the code execution will happen immediately on markdown view mode.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-06-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: znote

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

Am I affected?

Timeline

2021-06-18 12:15 UTCPublished CVE record published
2026-06-17 03:43 UTCUpdated Record last modified

znote znote DOWNGRADE

Affected: 0.5.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.5.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.5.2 (Debian / Ubuntu)

apt-cache madison znote sudo apt install znote=<VERSION_BEFORE_0.5.2> sudo apt-mark hold znote

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

dnf --showduplicates list znote sudo dnf downgrade znote-<VERSION_BEFORE_0.5.2> sudo dnf versionlock add znote

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-2021-26834?

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

Is CVE-2021-26834 being exploited?

CVE-2021-26834 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-2021-26834 affect?

CVE-2021-26834 affects znote. Severity is medium (CVSS 5.4). A cross-site scripting (XSS) vulnerability exists in Znote 0.5.2. An attacker can insert payloads, and the code execution will happen immediately on markdown view mode.

How urgent is CVE-2021-26834?

Priority 37/100. Public exploit reference

Related CVEs

CVE-2022-4614 MEDIUM 5.4 UPGRADE Cross-site Scripting (XSS) - Stored in GitHub repository alagrede/znote-app prior to 1.7.11.

References

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