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Fencer Intel
low 3.7

CVE-2026-35537 json

Roundcube Webmail: Unsafe deserialization in the redis/memcache session handler

published 7mo ago modified 3mo ago also GHSA-rxj3-rrwm-pj4r , EUVD-2026-18575

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist roundcube/roundcubemail 1.7-rc5
  • Roundcube Webmail 1.5.14, 1.6.14
  • roundcube Debian 12 1.6.5+dfsg-1+deb12u8
  • roundcube Debian 13 1.6.15+dfsg-0+deb13u1
  • roundcube Debian 14 1.6.14+dfsg-1

debian advisories DEBIAN-CVE-2026-35537

  • roundcubemail openSUSE Leap 16.0 1.6.15-bp160.1.1

opensuse advisories openSUSE-SU-2026:20586-1

Is CVE-2026-35537 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-35537 updated cvss 3.7

roundcubemail: Roundcube Webmail: Arbitrary file write via unsafe deserialization in session handler

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist roundcube/roundcubemail
>=1.7-beta, <1.7-rc5
1.7-rc5

Affected products

  • Roundcube Webmail

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.