How severe is CVE-2020-27507?

CVE-2020-27507 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-2020-27507 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27507?

CVE-2020-27507 affects Kamailio. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-27507?

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-2020-27507 published?

CVE-2020-27507 was published on 2023-03-15 and last updated on 2026-06-17.

CVE-2020-27507

CVE-2020-27507 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-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Kamailio
Published: 2023-03-15
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-27507?: 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.
How severe is CVE-2020-27507?: CVE-2020-27507 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-2020-27507 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27507?: CVE-2020-27507 affects Kamailio. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-27507?: 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-2020-27507 published?: CVE-2020-27507 was published on 2023-03-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:kamailio:kamailio:*:*:*:*:*:*:*:*

More vulnerabilities in Kamailio

CVE-2018-16657 — Critical (CVSS 9.8): 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…
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 →

Other CWE-120 (Classic Buffer Overflow) vulnerabilities

CVE-2025-48611 — Critical (CVSS 10.0): In DeviceId of DeviceId.java, there is a possible desync in persistence due to a missing bounds check. This could lead…
CVE-2026-24823 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in FASTSHIFT…
CVE-2026-24810 — Critical (CVSS 10.0): Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in rethinkdb (src/cjson modules).…
CVE-2026-24800 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in tildearrow…
CVE-2025-9962 — Critical (CVSS 10.0): A buffer overflow vulnerability in Novakon P series allows attackers to gain root permission without prior…
CVE-2010-10016 — Critical (CVSS 10.0): BS.Player version 2.57 (build 1051) contains a vulnerability in its playlist import functionality. When processing .m3u…

Browse all CWE-120 (Classic Buffer Overflow) vulnerabilities →