Vulnerability in Ellite Wallos

CVE-2026-77353

Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 5.0.0, Wallos allows authenticated users to inject arbitrary iCalendar properties and events into their exported .ics feed by embedding raw CRLF sequences in subscription names or notes. Because the input validation layer only encodes HTML metacharacters but never strips newlines, and the export layer decodes those entities back before writing iCal output, an attacker with any valid account can craft a subscription whose name breaks out of the current VEVENT block and inserts fully attacker-controlled calendar events — including spoofed organizers, arbitrary email addresses in ATTENDEE properties, and misleading event content — into any calendar application subscribed to that feed. This issue has been patched in version 5.0.0.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (20.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-77353: held from 0.002 to 0.003.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-77353?
CVE-2026-77353 is a medium-severity vulnerability in Ellite Wallos, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 4.6/10. Published 2026-08-31.
How severe is CVE-2026-77353?
Medium severity. CVSS v3 base score is 4.6 out of 10.