Skip to content
Noroxi
NVD / CVE Program· CNA mitre

CVE-2026-74998: In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which…

HighCVSS 7.2 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.32% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Roundcube Webmail 1.6.18, 1.7.3.

Low priority for now. Upgrade to Roundcube Webmail 1.6.18, 1.7.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.

Published
Aug 17, 2026
Updated
Sep 8, 2026
EPSS
0.3% · 25th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · mitre
7.2
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-74998

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Limit the impact of XSSCheck security headers

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for roundcube records

Limit the impact of XSSCheck security headers

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
roundcubewebmail

Using webmail? Add it to your stack and be the first to know about CVEs like this one. (Email server)

Watch new CVEs for webmail

When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or is weaponized

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Limit the impact of XSSCheck security headers

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every Monday

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mitre). Independent of NVD's CPE analysis and usually ahead of it.

  • Roundcube Webmail

    • 1.6.0 and later · before 1.6.18affected · semver
    • 1.7.0 and later · before 1.7.3affected · semver

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • roundcube webmail1.6.0 and later · before 1.6.18
  • roundcube webmail1.7.0 and later · before 1.7.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12roundcubebefore 1.6.5+dfsg-1+deb12u111.6.5+dfsg-1+deb12u11
Debian:13roundcubebefore 1.6.18+dfsg-0+deb13u11.6.18+dfsg-0+deb13u1
Debian:14roundcubebefore 1.6.18+dfsg-11.6.18+dfsg-1
openSUSE:Leap 16.0roundcubemailbefore 1.6.20-bp160.1.11.6.20-bp160.1.1
openSUSE:Tumbleweedroundcubemailbefore 1.6.19-1.11.6.19-1.1

Same product

roundcube: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-49113Roundcube Webmail before 1.5.10 and 1.6.x before 1.6.11 allows remote code execution by authenticated users because the _from parameter in…KEV
    95Now
  • CVE-2020-12641rcube_image.php in Roundcube Webmail before 1.4.4 allows attackers to execute arbitrary code via shell metacharacters in a configuration…KEV
    94Now
  • CVE-2024-42009A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through 1.6.7 allows a remote attacker to steal and send emails…KEV
    92Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-54433Jul 14, 2026 · In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, there is Stored Cross-Site Scripting (XSS) via a crafted plain-text email…
    40Plan
  • ← EarlierCVE-2026-74997Aug 17, 2026 · 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…
    35Monitor
  • Later →CVE-2026-74999Aug 17, 2026 · In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the "Add to address book" action was subject to stored XSS.
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Roundcube Webmail1.6.18Vendor (CNA)
Roundcube Webmail1.7.3Vendor (CNA)
debian:roundcube1.6.5+dfsg-1+deb12u11 · Debian:12Package registry (OSV)
opensuse:roundcubemail1.6.19-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-68461242 days apartRoundcube Webmail before 1.5.12 and 1.6 before 1.6.12 is prone to a Cross-Site-Scripting (XSS) vulnerability via the animate tag in an SVG…KEV
    62This week
  • CVE-2026-5443334 days apartIn Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, there is Stored Cross-Site Scripting (XSS) via a crafted plain-text email…
    40Plan
  • CVE-2026-4884884 days apartRoundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7 has insufficient HTML sanitization that could lead to Cascading Style Sheets…
    28Monitor
  • CVE-2026-11471866 days apartRoundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a cross-site scripting vulnerability in the password plugin.
    24Monitor
  • CVE-2026-35539136 days apartAn issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14.
    24Monitor
  • CVE-2026-749990 days apartIn Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the "Add to address book" action was subject to stored XSS.
    21Monitor

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: researcher credit.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

nvd-secondary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records