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CVE-2021-43610

24
FAUCET Score

CVE-2021-43610 is a high-severity vulnerability affecting Belledonne Belle-sip versions prior to 5.0.20, including applications like Linphone. It allows an unauthenticated attacker to crash affected applications by sending a specially crafted SIP message with an invalid From header. The vulnerability has a CVSS score of 7.5, indicating a high impact on availability with no confidentiality or integrity impact. There is currently no public exploit code available, no evidence of active exploitation, and minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.0.20CPE matchmatch criteria
cpe:2.3:a:linphone:belle-sip:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.15%
Probability of exploitation in next 30 days
EPSS Percentile
63.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0115 is in the 42nd percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / BelledonneCommunications/belle-sip/commit/d3f0651531e45e91c2e60f3a16a8b612802e5d2d
PatchThird Party Advisory
github.com / BelledonneCommunications/belle-sip/compare/5.0.18...5.0.20
PatchThird Party Advisory