libical through 4.0.6 contains a heap-based out-of-bounds read in icalvalue_decode_ical_string() in src/libical/icalvalue.c when decoding input ending in a backslash. Attackers can supply escaped iCalendar text with a trailing backslash, causing the loop to read past the terminator and crash the application or leak adjacent heap memory.
https://hackmd.io/@haind-pwn/libical-icalvalue-decode-ical-string-oob-read
https://github.com/libical/libical/pull/1455
https://github.com/libical/libical/commit/d753885ce2de7c105d6b8c405aa7aee1d98ad8de
Published: 2026-10-15
Updated: 2026-10-16
Base Score: 5.6
Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:C
Severity: Medium
Base Score: 6.1
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Severity: Medium
Base Score: 6.9
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00129