How severe is CVE-2021-43610?

CVE-2021-43610 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-43610 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43610?

CVE-2021-43610 affects Linphone Belle-sip. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43610?

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

When was CVE-2021-43610 published?

CVE-2021-43610 was published on 2021-11-12 and last updated on 2026-06-17.

CVE-2021-43610

CVE-2021-43610 is a high-severity vulnerability in Linphone Belle-sip with a CVSS 3.x base score of 7.5. 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: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-444
Affected product: Linphone Belle-sip
Published: 2021-11-12
Last modified: 2026-06-17

Description

Belledonne Belle-sip before 5.0.20 can crash applications such as Linphone via an invalid From header (request URI without a parameter) in an unauthenticated SIP message, a different issue than CVE-2021-33056.

Frequently asked questions

What is CVE-2021-43610?: Belledonne Belle-sip before 5.0.20 can crash applications such as Linphone via an invalid From header (request URI without a parameter) in an unauthenticated SIP message, a different issue than CVE-2021-33056.
How severe is CVE-2021-43610?: CVE-2021-43610 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-43610 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43610?: CVE-2021-43610 affects Linphone Belle-sip. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43610?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-43610 published?: CVE-2021-43610 was published on 2021-11-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:linphone:belle-sip:*:*:*:*:*:*:*:*

More vulnerabilities in Linphone Belle-sip

CVE-2021-43611 — High (CVSS 7.5): Belledonne Belle-sip before 5.0.20 can crash applications such as Linphone via " \ " in the display name of a From…
CVE-2021-33056 — High (CVSS 7.5): Belledonne Belle-sip before 4.5.20, as used in Linphone and other products, can crash via an invalid From header in a…

All CVEs affecting Linphone Belle-sip →

Other CWE-444 (HTTP Request/Response Smuggling) vulnerabilities

CVE-2025-1867 — Critical (CVSS 10.0): Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in ithewei libhv allows…
CVE-2022-22536 — Critical (CVSS 10.0): SAP NetWeaver Application Server ABAP, SAP NetWeaver Application Server Java, ABAP Platform, SAP Content Server 7.53…
CVE-2018-3907 — Critical (CVSS 10.0): An exploitable vulnerability exists in the REST parser of video-core's HTTP server of the Samsung SmartThings Hub…
CVE-2025-55315 — Critical (CVSS 9.9): Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an authorized…
CVE-2020-15049 — Critical (CVSS 9.9): An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request…
CVE-2026-13763 — Critical (CVSS 9.8): Inconsistent interpretation of HTTP/2 requests in AWS Application Load Balancer with AWS WAF enabled might allow remote…

Browse all CWE-444 (HTTP Request/Response Smuggling) vulnerabilities →