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Mail header injection in Roundcube Webmail bounce action

Priority LOW 32CWE-99Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

Roundcube Webmail from 1.6.0 before 1.6.20 and from 1.7.0 before 1.7.5 is affected. Control characters are not stripped from the decoded display name of a From address, which is tracked as CWE-99. An unauthenticated remote attacker can send a message whose encoded From display name contains CRLF sequences, so arbitrary headers are injected into the message emitted when the user bounces it.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a mail header injection vulnerability in the Bounce (resend) action. rcube_mime::decode_address_list() did not strip control characters from the decoded display name, so a received message whose From display-name carries CRLF sequences in an encoded word could inject arbitrary headers into the message emitted when the user bounces it. Upstream fixed this in the commit “Fix mail header injection via the From display-name in the Bounce (resend) action”.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00397 34th percentileScored 2026-11-07
Fix Fixed Webmail (Roundcube): 1.6.20, 1.7.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
RoundcubeWebmail1.6.0 to before 1.6.20; 1.7.0 to before 1.7.51.6.20, 1.7.5Patch availableCNA
  • Webmail VendorRoundcube Affected 1.6.0 to before 1.6.20; 1.7.0 to before 1.7.5 Fixed in 1.6.20, 1.7.5 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*1.6.0 to before 1.6.20; 1.7.0 to before 1.7.5VulnerableRoundcube
  • cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:* Versions 1.6.0 to before 1.6.20; 1.7.0 to before 1.7.5 Vulnerable ·Roundcube

Remediation

Upgrade to 1.6.20 or 1.7.5, the fixed versions for the affected ranges. Use the release that matches the installed series.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA Webmail (Roundcube) Fixed in 1.6.20, 1.7.5

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    Roundcube Webmail — roundcube.net/news/2026/10/19/security-updates-1.6.20-and-1…

    20 records Highest priority Priority LOW 20 LOW

    Other records, highest priority first

    • TI-2026-79180 Server-side request forgery filter bypass in Roundcube WebmailPriority LOW 38
    • TI-2026-79177 Roundcube Webmail passes unsafe SVG and EPS content to ImageMagickPriority LOW 38
    • TI-2026-79182 Improper authentication in Roundcube Webmail multi-host alias loginsPriority LOW 37

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-114726
  2. 2026-10-22 Alias added: GHSA-hpmj-jmwh-pghr
  3. 2026-10-23 Priority changed: MEDIUM → LOW
  4. 2026-10-28 CISA SSVC decision points changed
  5. 2026-10-29 Affected versions changed · Red Hat
  6. 2026-10-29 CVSS score added · Red Hat

References

  • TI-2025-31204 Deserialization of untrusted data in Roundcube Webmail KEVCVSS 3.1CRITICAL 9.9
  • TI-2021-19778 Roundcube before 1.3.17 and 1.4.x before 1.4.12 is prone to a potential SQL injection via search or search_params. KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-10051 rcube_image.php in Roundcube Webmail before 1.4.4 allows attackers to execute arbitrary… KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-28025 A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through 1.6.7… KEVCVSS 3.1CRITICAL 9.3
  • TI-2017-12250 Roundcube Webmail before 1.1.10, 1.2.x before 1.2.7, and 1.3.x before 1.3.3 allows… KEVCVSS 3.1HIGH 7.8
  • TI-2025-41994 Cross-site scripting in Roundcube Webmail KEVCVSS 3.1HIGH 7.2
See all 112 →

Sources