PatchTheCVECVE-2026-49420: The RTSP handler in libalias rewrote outgoing packets into a fixed-length stack buffer without checking whethe
CVE-2026-49420 is a high-severity flaw (CVSS 8.8) affecting freebsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
The RTSP handler in libalias rewrote outgoing packets into a fixed-length stack buffer without checking whether the rewritten data fit in the buffer, or whether the result fit back in the original packet. A host sending crafted RTSP traffic from inside a NAT gateway using libalias can overflow a stack buffer, potentially achieving remote code execution in the kernel (when using ipfw(4) NAT) or in the natd(8) process (which generally runs as the
Why this priority
- High severity
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 8.8 (High) |
| Attack vector | Adjacent network |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.4% (top 64%) |
| CISA exploited list | No |
| Weakness | CWE-121 |
| Published | 2026-08-19 |
| Last modified | 2026-09-01 |
Last updated 2026-09-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-49420?
freebsd: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2026-49420 being exploited?
CVE-2026-49420 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-49420 affect?
CVE-2026-49420 affects freebsd. Severity is high (CVSS 8.8). The RTSP handler in libalias rewrote outgoing packets into a fixed-length stack buffer without checking whether the rewritten data fit in the buffer, or whether the result fit back in the original packet. A host sending crafted RTSP traffi
How urgent is CVE-2026-49420?
Priority 40/100. High severity
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