CVE-2023-27390: A heap-based buffer overflow vulnerability exists in the Sequence::DrawText functionality of Diagon v1.0.139

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HIGH 7.8DOWNGRADE

CVE-2023-27390 is a high-severity flaw (CVSS 7.8) affecting diagon. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A heap-based buffer overflow vulnerability exists in the Sequence::DrawText functionality of Diagon v1.0.139. A specially crafted markdown file can lead to arbitrary code execution. A victim would need to open a malicious file to trigger this vulnerability.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.5% (top 56%)
CISA exploited list	No
Weakness	CWE-122, CWE-787
Published	2023-07-05
Last modified	2026-06-17

Publisher (CNA): Talos · Vendor: diagon project

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

Am I affected?

Timeline

2023-07-05 16:15 UTCPublished CVE record published
2026-06-17 05:44 UTCUpdated Record last modified

diagon project diagon DOWNGRADE

Affected: 1.0.139

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.139

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.0.139 (Debian / Ubuntu)

apt-cache madison diagon sudo apt install diagon=<VERSION_BEFORE_1.0.139> sudo apt-mark hold diagon

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

dnf --showduplicates list diagon sudo dnf downgrade diagon-<VERSION_BEFORE_1.0.139> sudo dnf versionlock add diagon

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-2023-27390?

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

Is CVE-2023-27390 being exploited?

CVE-2023-27390 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-2023-27390 affect?

CVE-2023-27390 affects diagon. Severity is high (CVSS 7.8). A heap-based buffer overflow vulnerability exists in the Sequence::DrawText functionality of Diagon v1.0.139. A specially crafted markdown file can lead to arbitrary code execution. A victim would need to open a malicious file to trigger th

How urgent is CVE-2023-27390?

Priority 43/100. High severity; Public exploit reference

Related CVEs

CVE-2023-31194 MEDIUM 5.3 DOWNGRADE An improper array index validation vulnerability exists in the GraphPlanar::Write functionality of Diagon v1.0

References

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