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High CVSS 8.8

CVE-2026-49420

NVD analysis in progress

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 root user).

What this means

Exposure
Exploitable from the adjacent network, without authentication and with no action from the victim.
Impact
An attacker can read sensitive data, modify or destroy data and take the service offline.
Weakness
A stack overflow overwrites the return address, which often leads to code execution.
Likelihood
Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.

What to doFold into the next patch cycle.

Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.

Published
19 August 2026
CVSS
8.8 (v3.1) CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.27% probability of exploitation within 30 days · above 19% of all CVEs
Weakness
CWE-121
Sources
nvd
References

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