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VulnerabilityPublished

CVE-2026-35542: Roundcube Webmail · Incorrect Resource Transfer Between Spheres

Affects Roundcube WebmailSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.6.14 or 1.5.14 when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.6.14, 1.5.14
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade Webmail and roundcube/roundcubemail to 1.6.14 or 1.5.14.

Affected software

ProductAffectedFixed in
RoundcubeWebmailAffected
  • >=1.6.0 <1.6.14
Fixed in
  • 1.6.14
RoundcubeWebmailAffected
  • <1.5.14
Fixed in
  • 1.5.14
GitHubroundcube/roundcubemailpkg:github/roundcube/roundcubemailOther threatsAffected
  • <1.5.14
  • >=1.6.0 <1.6.14
  • =1.6.0
Fixed in
  • 1.5.14
  • 1.6.14

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, consider applying temporary mitigations such as disabling remote image loading or restricting email content rendering features if feasible.

Description

CVE-2026-35542 is a medium severity vulnerability in Roundcube Webmail versions before 1.5.14 and 1.6.14. It allows bypassing the remote image blocking feature through a crafted background attribute in the BODY element of an email message. This bypass can lead to information disclosure or access-control bypass. The vulnerability is related to incorrect resource transfer between security spheres (CWE-669).

References

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