CVE-2020-11556: An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28

Routine

MEDIUM 5.4UPGRADE

CVE-2020-11556 is a medium-severity flaw (CVSS 5.4) affecting snmpc online. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28. There are multiple persistent (stored) and reflected XSS vulnerabilities.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

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 54%)
CISA exploited list	No
Weakness	CWE-79
Published	2020-04-09
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: castlerock

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

Am I affected?

Timeline

2020-04-09 13:15 UTCPublished CVE record published
2026-06-17 02:50 UTCUpdated Record last modified

castlerock snmpc online UPGRADE

Affected: >= 12.10.10 and < 2020-01-28

Fixed in: 2020-01-28

Safe to downgrade to: a release before 12.10.10

1. Check installed version

apt-cache policy snmpc-online || rpm -q snmpc-online || snmpc-online --version

2. UPGRADE to 2020-01-28 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade snmpc-online

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade snmpc-online

Note

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

3. If no update is available yet, DOWNGRADE to a release before 12.10.10 (Debian / Ubuntu)

apt-cache madison snmpc-online sudo apt install snmpc-online=<VERSION_BEFORE_12.10.10> sudo apt-mark hold snmpc-online

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list snmpc-online sudo dnf downgrade snmpc-online-<VERSION_BEFORE_12.10.10> sudo dnf versionlock add snmpc-online

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-2020-11556?

snmpc online: upgrade to 2020-01-28. Exact commands for each OS are on this page.

Is CVE-2020-11556 being exploited?

CVE-2020-11556 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-2020-11556 affect?

CVE-2020-11556 affects snmpc online. Severity is medium (CVSS 5.4). An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28. There are multiple persistent (stored) and reflected XSS vulnerabilities.

How urgent is CVE-2020-11556?

Priority 36/100. Public exploit reference

Related CVEs

CVE-2020-11557 HIGH 7.5 UPGRADE An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28
CVE-2020-11555 HIGH 7.5 UPGRADE An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28
CVE-2020-11554 HIGH 7.5 UPGRADE An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28
CVE-2020-11553 HIGH 8.8 UPGRADE An issue was discovered in Castle Rock SNMPc Online 12.10.10 before 2020-01-28

References

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