CVE-2019-12136: There is XSS in BoostIO Boostnote 0.11.15 via a label named mermaid, as demonstrated by a crafted SRC attribut

Routine

MEDIUM 5.4DOWNGRADE

CVE-2019-12136 is a medium-severity flaw (CVSS 5.4) affecting boostnote. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

There is XSS in BoostIO Boostnote 0.11.15 via a label named mermaid, as demonstrated by a crafted SRC attribute of an IFRAME element.

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	0.6% (top 51%)
CISA exploited list	No
Weakness	CWE-79
Published	2019-05-16
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: boostio

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

Am I affected?

Timeline

2019-05-16 03:29 UTCPublished CVE record published
2026-06-17 02:14 UTCUpdated Record last modified

boostio boostnote DOWNGRADE

Affected: 0.11.15

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.11.15

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.11.15 (Debian / Ubuntu)

apt-cache madison boostnote sudo apt install boostnote=<VERSION_BEFORE_0.11.15> sudo apt-mark hold boostnote

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

dnf --showduplicates list boostnote sudo dnf downgrade boostnote-<VERSION_BEFORE_0.11.15> sudo dnf versionlock add boostnote

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-2019-12136?

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

Is CVE-2019-12136 being exploited?

CVE-2019-12136 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-2019-12136 affect?

CVE-2019-12136 affects boostnote. Severity is medium (CVSS 5.4). There is XSS in BoostIO Boostnote 0.11.15 via a label named mermaid, as demonstrated by a crafted SRC attribute of an IFRAME element.

How urgent is CVE-2019-12136?

Priority 36/100. Public exploit reference

Related CVEs

CVE-2021-41392 CRITICAL 9.8 UPGRADE static/main-preload.js in Boost Note through 0.22.0 allows remote command execution
CVE-2020-19924 MEDIUM 5.4 DOWNGRADE In Boostnote 0.12.1, exporting to PDF contains opportunities for XSS attacks.
CVE-2019-12184 MEDIUM 5.4 DOWNGRADE There is XSS in browser/components/MarkdownPreview.js in BoostIO Boostnote 0.11.15 via a label named flowchart
CVE-2018-13433 MEDIUM 6.1 DOWNGRADE Boostnote v0.11.7 allows XSS during highlighting of Markdown text, as demonstrated by an onerror attribute of

References

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