CVE-2019-11455: A buffer over-read in Util_urlDecode in util.c in Tildeslash Monit before 5.25.3 allows a remote authenticated

Q: How do I fix CVE-2019-11455?

monit: upgrade to 5.25.3; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2019-11455 being exploited?

CVE-2019-11455 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-2019-11455 affect?

CVE-2019-11455 affects monit, debian linux, fedora. Severity is high (CVSS 8.1). A buffer over-read in Util_urlDecode in util.c in Tildeslash Monit before 5.25.3 allows a remote authenticated attacker to retrieve the contents of adjacent memory via manipulation of GET or POST parameters. The attacker can also cause a de

Q: How urgent is CVE-2019-11455?

Priority 60/100. High severity; Public exploit reference; On your watchlist

This week

HIGH 8.1WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2019-11455 is a high-severity flaw (CVSS 8.1) affecting monit, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A buffer over-read in Util_urlDecode in util.c in Tildeslash Monit before 5.25.3 allows a remote authenticated attacker to retrieve the contents of adjacent memory via manipulation of GET or POST parameters. The attacker can also cause a denial of service (application outage).

Why this priority

High severity
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-125
Published	2019-04-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · fedoraproject · tildeslash

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

Am I affected?

Timeline

2019-04-22 16:29 UTCPublished CVE record published
2026-06-17 02:12 UTCUpdated Record last modified

tildeslash monit UPGRADE

Affected: < 5.25.3

Fixed in: 5.25.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 5.25.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade monit

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade monit

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

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.

fedoraproject fedora MITIGATE

Affected: 31 · 32

Fixed in: no fixed release known

Safe to downgrade to: a release before 31

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.

canonical ubuntu linux MITIGATE

Affected: 18.10 · 19.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 18.10

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-2019-11455?

monit: upgrade to 5.25.3; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-11455 being exploited?

CVE-2019-11455 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-2019-11455 affect?

CVE-2019-11455 affects monit, debian linux, fedora. Severity is high (CVSS 8.1). A buffer over-read in Util_urlDecode in util.c in Tildeslash Monit before 5.25.3 allows a remote authenticated attacker to retrieve the contents of adjacent memory via manipulation of GET or POST parameters. The attacker can also cause a de

How urgent is CVE-2019-11455?

Priority 60/100. High severity; Public exploit reference; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2022-26563 HIGH 8.8 UPGRADE An issue was discovered in Tildeslash Monit before 5.31.0, allows remote attackers to gain escilated privlidge
CVE-2019-11454 MEDIUM 6.1 UPGRADE MITIGATE Persistent cross-site scripting (XSS) in http/cervlet.c in Tildeslash Monit before 5.25.3 allows a remote unau
CVE-2019-11393 CRITICAL 9.8 UPGRADE An issue was discovered in /admin/users/update in M/Monit before 3.7.3
CVE-2016-7067 MEDIUM 6.5 UPGRADE Monit before version 5.20.0 is vulnerable to a cross site request forgery attack

References

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