Medium (5.4) in kamailio kamailio. EPSS 1.1% chance of exploitation in the next 30 days.
Kamailio before 5.4.0, as used in Sip Express Router (SER) in Sippy Softswitch 4.5 through 5.2 and other products, allows a bypass of a header-removal protection mechanism via whitespace characters. This occurs in the remove_hf function in the Kamailio textops module. Particular use of remove_hf in Sippy Softswitch may allow skilled attacker having a valid credential in the system to disrupt internal call start/duration accounting mechanisms leading potentially to a loss of revenue.
Severity
CVSS 3.1
5.4 medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
EPSS
1.1% chance of exploitation in the next 30 days; higher than 65% of CVEs (scores of 2026-10-31)