Kamailio: >> Kamailio >> 5.1.0 Security Vulnerabilities
Kamailio is an open source implementation of a SIP Signaling Server. Prior to 6.1.1, 6.0.6, and 5.8.8, an out-of-bounds access in the core of Kamailio (formerly OpenSER and SER) allows remote attackers to cause a denial of service (process crash) via a specially crafted data packet sent over TCP. The issue impacts Kamailio instances having TCP or TLS listeners. This vulnerability is fixed in 5.1.1, 6.0.6, and 5.8.8.
CVSS Score
7.5
EPSS Score
0.0
Published
2026-04-08
Kamailio is an open source implementation of a SIP Signaling Server. Prior to 6.0.5 and 5.8.7, an out-of-bounds read in the auth module of Kamailio (formerly OpenSER and SER) allows remote attackers to cause a denial of service (process crash) via a specially crafted SIP packet if a successful user authentication without a database backend is followed by additional user identity checks. This vulnerability is fixed in 6.0.5 and 5.8.7.
CVSS Score
4.4
EPSS Score
0.002
Published
2026-04-08
The Kamailio SIP before 5.5.0 server mishandles INVITE requests with duplicated fields and overlength tag, leading to a buffer overflow that crashes the server or possibly have unspecified other impact.
CVSS Score
9.8
EPSS Score
0.001
Published
2023-03-15
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.
CVSS Score
5.4
EPSS Score
0.001
Published
2020-11-18
In Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with an invalid Via header causes a segmentation fault and crashes Kamailio. The reason is missing input validation in the crcitt_string_array core function for calculating a CRC hash for To tags. (An additional error is present in the check_via_address core function: this function also misses input validation.) This could result in denial of service and potentially the execution of arbitrary code.
CVSS Score
9.8
EPSS Score
0.009
Published
2018-09-07
In Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with a double "To" header and an empty "To" tag causes a segmentation fault and crash. The reason is missing input validation in the "build_res_buf_from_sip_req" core function. This could result in denial of service and potentially the execution of arbitrary code.
CVSS Score
9.8
EPSS Score
0.011
Published
2018-07-31
A Buffer Overflow issue was discovered in Kamailio before 4.4.7, 5.0.x before 5.0.6, and 5.1.x before 5.1.2. A specially crafted REGISTER message with a malformed branch or From tag triggers an off-by-one heap-based buffer overflow in the tmx_check_pretran function in modules/tmx/tmx_pretran.c.
CVSS Score
9.8
EPSS Score
0.033
Published
2018-03-20