CVE-2020-28361

Name: CVE-2020-28361
Creator: NVD / NIST
Published: 2020-11-18T14:15:12.017+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 1.09%

Last modified Jun 17, 2026

CVE-2020-28361 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. 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. EPSS estimates a 1.09% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

5.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

1.09%

61.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-444

Affected Software

Vendor	Product	Versions
Kamailio	Kamailio	< 5.4.0

References

https://packetstormsecurity.com/files/159030/Kamailio-5.4.0-Header-Smuggling.htmlExploit, Third Party Advisory, VDB Entry
https://support.sippysoft.com/support/discussions/topics/3000179616Permissions Required
https://packetstormsecurity.com/files/159030/Kamailio-5.4.0-Header-Smuggling.htmlExploit, Third Party Advisory, VDB Entry
https://support.sippysoft.com/support/discussions/topics/3000179616Permissions Required

Timeline

Published: Nov 18, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-28361?

How severe is CVE-2020-28361?

CVE-2020-28361 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 1.09% probability of exploitation in the next 30 days.

How do I fix CVE-2020-28361?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-28361?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST