CVE-2026-35542: Roundcube Webmail · Incorrect Resource Transfer Between Spheres
Affects Roundcube WebmailSource CVE Database V5
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
- 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:NExploitation evidence
Disclosed: evidence found.
CVE published 3 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| RoundcubeWebmail | Affected
| Fixed in
|
| RoundcubeWebmail | Affected
| Fixed in
|
GitHubroundcube/roundcubemailpkg:github/roundcube/roundcubemailOther threats | Affected
| Fixed in
|
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
- roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14 (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.7-rc5 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/fd0e98178db5c73eaa93d005b561874923f9b0f0 (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.6.14 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/fde14d01adc9f37893cd82b635883e516ed453f8 (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.5.14 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/e052328e3dc75f13adc2e314eaa4096ac21084ad (opens in a new tab)