How severe is CVE-2020-28361?

CVE-2020-28361 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-28361 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-28361?

CVE-2020-28361 affects Kamailio. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-28361?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-28361 published?

CVE-2020-28361 was published on 2020-11-18 and last updated on 2026-06-17.

CVE-2020-28361

CVE-2020-28361 is a medium-severity vulnerability in Kamailio with a CVSS 3.x base score of 5.4. 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-444.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 5.5
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-444
Affected product: Kamailio
Published: 2020-11-18
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2020-28361?: 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.
How severe is CVE-2020-28361?: CVE-2020-28361 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-28361 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-28361?: CVE-2020-28361 affects Kamailio. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-28361?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-28361 published?: CVE-2020-28361 was published on 2020-11-18 and last updated on 2026-06-17.

References

Affected products (1)

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…
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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…
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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…

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