CVE-2026-35537: Roundcube Webmail · Deserialization of Untrusted Data
Affects Roundcube WebmailSource CVE Database V5
Not known to be exploited · CVSS 3.7 Low : upgrade to 1.6.14 or 1.5.14 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% 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:H/PR:N/UI:N/S:U/C:N/I:L/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 30 Oct 2026.
What to do
Upgrade Roundcube Webmail 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 disabling or restricting use of the redis/memcache session handler if feasible to reduce exposure.
Description
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Unsafe deserialization in the redis/memcache session handler may lead to arbitrary file write operations by unauthenticated attackers via crafted session data.
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/6d586cfa4d8a31f7957f7a445aaedd52592a0e74 (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.6.14 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/a4ead994d2f0ea92e4a1603196a197e0d5df1620 (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.5.14 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/618c5428edc69fb088e7ac6c89e506dd39df3 (opens in a new tab)
- openwall.com/lists/oss-security/2026/04/11/6 (opens in a new tab)