CVE-2019-12835: formats/xml.cpp in Leanify 0.4.3 allows for a controlled out-of-bounds write in xml_memory_writer::write via c

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2019-12835 is a critical-severity flaw (CVSS 9.8) affecting leanify. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

formats/xml.cpp in Leanify 0.4.3 allows for a controlled out-of-bounds write in xml_memory_writer::write via characters that require escaping.

Why this priority

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

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.6% (top 24%)
CISA exploited list	No
Weakness	CWE-787
Published	2019-06-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: leanify project

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

Am I affected?

Timeline

2019-06-15 19:29 UTCPublished CVE record published
2026-06-17 02:15 UTCUpdated Record last modified

leanify project leanify DOWNGRADE

Affected: 0.4.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.4.3

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.4.3 (Debian / Ubuntu)

apt-cache madison leanify sudo apt install leanify=<VERSION_BEFORE_0.4.3> sudo apt-mark hold leanify

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

dnf --showduplicates list leanify sudo dnf downgrade leanify-<VERSION_BEFORE_0.4.3> sudo dnf versionlock add leanify

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-2019-12835?

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

Is CVE-2019-12835 being exploited?

CVE-2019-12835 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-2019-12835 affect?

CVE-2019-12835 affects leanify. Severity is critical (CVSS 9.8). formats/xml.cpp in Leanify 0.4.3 allows for a controlled out-of-bounds write in xml_memory_writer::write via characters that require escaping.

How urgent is CVE-2019-12835?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-12298 MEDIUM 5.5 DOWNGRADE Leanify 0.4.3 allows remote attackers to trigger an out-of-bounds write (1024 bytes) via a modified input file

References

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