CVE-2026-74997: In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the cmd_learn driver of the markasjunk plugin is su

This month

HIGH 8.8UPGRADE

CVE-2026-74997 is a high-severity flaw (CVSS 8.8) affecting webmail. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the cmd_learn driver of the markasjunk plugin is subject to remote code execution via crafted placeholder replacement values. This issue only affects Roundcube instances using the markasjunk plugin with its cmd_learn driver.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.1% (top 34%)
CISA exploited list	No
Weakness	CWE-78
Published	2026-08-17
Last modified	2026-09-08

Publisher (CNA): MITRE · Vendor: roundcube

Last updated 2026-09-08 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-17 13:16 UTCPublished CVE record published
2026-09-08 19:09 UTCUpdated Record last modified

roundcube webmail UPGRADE

Affected: >= 1.6.0 and < 1.6.18 · >= 1.7.0 and < 1.7.3

Fixed in: 1.6.18, 1.7.3

Safe to downgrade to: a release before 1.6.0

1. Check installed version

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

2. UPGRADE to 1.6.18 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade webmail

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 1.6.0 (Debian / Ubuntu)

apt-cache madison webmail sudo apt install webmail=<VERSION_BEFORE_1.6.0> sudo apt-mark hold webmail

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

dnf --showduplicates list webmail sudo dnf downgrade webmail-<VERSION_BEFORE_1.6.0> sudo dnf versionlock add webmail

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-2026-74997?

webmail: upgrade to 1.6.18, 1.7.3. Exact commands for each OS are on this page.

Is CVE-2026-74997 being exploited?

CVE-2026-74997 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-2026-74997 affect?

CVE-2026-74997 affects webmail. Severity is high (CVSS 8.8). In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the cmd_learn driver of the markasjunk plugin is subject to remote code execution via crafted placeholder replacement values. This issue only affects Roundcube instances using the m

How urgent is CVE-2026-74997?

Priority 47/100. High severity

Software pages

Roundcube vulnerabilities

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References

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