High severity · published Apr 3, 2026
CVE-2026-35537
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14
7.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WE
Webmail · Roundcube
before 1.5.14; 1.6.0 before 1.6.14 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35537
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-35537
Patch
https://github.com/roundcube/roundcubemail/commit/618c5428edc69fb088e7ac6c89e506dd39df3
Patch
https://github.com/roundcube/roundcubemail/commit/6d586cfa4d8a31f7957f7a445aaedd52592a0e74
Patch
https://github.com/roundcube/roundcubemail/commit/a4ead994d2f0ea92e4a1603196a197e0d5df1620
Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.5.14
Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.6.14
Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5
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