How severe is CVE-2018-16657?

CVE-2018-16657 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-16657 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-16657?

CVE-2018-16657 primarily affects Kamailio. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-16657?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-16657 published?

CVE-2018-16657 was published on 2018-09-07 and last updated on 2026-06-17.

CVE-2018-16657

CVE-2018-16657 is a critical-severity vulnerability in Kamailio with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 4% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Kamailio
Published: 2018-09-07
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2018-16657?: 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.
How severe is CVE-2018-16657?: CVE-2018-16657 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-16657 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-16657?: CVE-2018-16657 primarily affects Kamailio. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-16657?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-16657 published?: CVE-2018-16657 was published on 2018-09-07 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:a:kamailio:kamailio:*:*:*:*:*:*:*:*

More vulnerabilities in Kamailio

CVE-2020-27507 — Critical (CVSS 9.8): The Kamailio SIP before 5.5.0 server mishandles INVITE requests with duplicated fields and overlength tag, leading to a…
CVE-2018-14767 — Critical (CVSS 9.8): 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…
CVE-2018-8828 — Critical (CVSS 9.8): 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…
CVE-2013-7426 — Critical (CVSS 9.8): Insecure Temporary file vulnerability in /tmp/kamailio_fifo in kamailio 4.0.1.
CVE-2016-2385 — Critical (CVSS 9.8): Heap-based buffer overflow in the encode_msg function in encode_msg.c in the SEAS module in Kamailio (formerly OpenSER…
CVE-2015-1590 — High (CVSS 7.8): The kamcmd administrative utility and default configuration in kamailio before 4.3.0 use /tmp/kamailio_ctl.

All CVEs affecting Kamailio →

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