Vulnerability · Published Aug 31, 2026 · Assigned by GitHub_M

CVE-2026-77353Wallos: iCalendar Injection via CRLF in Subscription Name/Notes Export

Medium 4.6

In plain English

A medium-severity injection in Wallos from ellite. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 3.1)4.6Medium

Exploit odds (30 days)0.3%top 78.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
ellite	Wallos	< 5.0.0

Weakness: CWE-74, CWE-116 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References

https://github.com/ellite/Wallos/security/advisories/GHSA-q2r8-m9wm-5547 x_refsource_CONFIRM
https://github.com/ellite/Wallos/commit/11eaf402e841a628c68a805694227ce66c45f6f3 x_refsource_MISC
https://github.com/ellite/Wallos/releases/tag/v5.0.0 x_refsource_MISC