CVE-2026-49420

Buffer overflow in libalias RTSP handler

HIGH
8.8
CVSS Score
Published: August 19, 2026 at 05:20 AM UTC
Updated: September 1, 2026 at 08:31 PM UTC
1 product affected across 1 vendorFreeBSD

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Severity
HIGH8.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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).

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below p1, so it looks safe — our inference, not a vendor statement
Affected range stops below p11, so it looks safe — our inference, not a vendor statement
Affected range stops below p16, so it looks safe — our inference, not a vendor statement
Affected range stops below p7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHCISA-ADP
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-121

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