How severe is CVE-2026-35537?

CVE-2026-35537 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-35537 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-35537?

CVE-2026-35537 affects Roundcube Webmail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-35537?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-35537 have an EU (EUVD) identifier?

Yes. CVE-2026-35537 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18575.

When was CVE-2026-35537 published?

CVE-2026-35537 was published on 2026-04-03 and last updated on 2026-06-17.

CVE-2026-35537

CVE-2026-35537 is a low-severity vulnerability in Roundcube Webmail with a CVSS 3.x base score of 3.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Low (CVSS 3.x base score 3.7)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18575
Weakness: CWE-502
Affected product: Roundcube Webmail
Published: 2026-04-03
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-35537?: 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.
How severe is CVE-2026-35537?: CVE-2026-35537 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-35537 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-35537?: CVE-2026-35537 affects Roundcube Webmail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-35537?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-35537 have an EU (EUVD) identifier?: Yes. CVE-2026-35537 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18575.
When was CVE-2026-35537 published?: CVE-2026-35537 was published on 2026-04-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*

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