A stack-based buffer overflow exists in Kamailio v6.1.3 and v6.1.4 in the ims_qos_npn module.
Affects Kamailio v6.1.3 and v6.1.4 when the ims_qos_npn module is loaded, REGISTER is routed through Rx_AAR_Register(), and the Rx interface is enabled. No fix is listed in the checked facts.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- Proof of concept public, per CISA
- Fix
- No fix listed
- Who is exposed
- Not reported
Do first: Workaround: The checked facts give no workaround. Limiting the affected feature, such as not loading ims_qos_npn or leaving the Rx interface disabled, would remove the stated conditions, but the facts do not confirm that this has been verified.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 38/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
Kamailio, an open-source SIP server, is affected when its IMS QoS NPN module is used. An unauthenticated remote attacker can send a specially crafted SIP REGISTER request that overflows a stack buffer, crashing the server and causing a denial of service.
Read the original description
A stack-based buffer overflow exists in Kamailio v6.1.3 and v6.1.4 in the ims_qos_npn module. The w_rx_aar_register() function copies the attacker-controlled host field from the SIP `Via` header into a fixed 46-byte stack buffer without validating its length. An unauthenticated remote attacker can trigger the vulnerability with a crafted SIP `REGISTER` request, causing stack corruption and termination of the affected Kamailio instance, resulting in denial of service.
What to do
Workaround: The checked facts give no workaround. Limiting the affected feature, such as not loading ims_qos_npn or leaving the Rx interface disabled, would remove the stated conditions, but the facts do not confirm that this has been verified.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Evidence 2
- Repository
- Link
Corrections
None so far.
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Questions about CVE-2026-106804
What does this mean?
A stack-based buffer overflow in the ims_qos_npn module corrupts stack memory and terminates the affected Kamailio process, which causes a denial of service.Source: github.com, gist.github.com
Am I affected, and how do I check?
The report says Kamailio v6.1.3 and v6.1.4 are affected, and the master branch too per the source analysis, when ims_qos_npn is loaded and REGISTER is routed through Rx_AAR_Register() with the Rx interface enabled. To check a setup, look at the installed Kamailio version and whether the module and routing are present in the configuration.Source: github.com, gist.github.com
What should I do about it?
The checked facts list no fixed version, so no upgrade target is given. Review whether ims_qos_npn is loaded and whether REGISTER is routed through Rx_AAR_Register() with the Rx interface enabled.Source: github.com, gist.github.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data
What if there's no patch?
The checked facts give no workaround. Limiting the affected feature, such as not loading ims_qos_npn or leaving the Rx interface disabled, would remove the stated conditions, but the facts do not confirm that this has been verified.Source: github.com, gist.github.com