VDB-420503 · CVE-2026-101302 · EUVD-2026-101870

FreeBSD Ktls off-by-one

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.2	$5k-$25k	5.34-

Summaryinfo

A vulnerability classified as critical has been found in FreeBSD. The affected element is an unknown function of the component Ktls. The manipulation leads to off-by-one. This vulnerability is listed as CVE-2026-101302. The attack may be initiated remotely. There is no available exploit. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability was found in FreeBSD (version now known) and classified as critical. This issue affects some unknown processing of the component Ktls. The manipulation with an unknown input leads to a off-by-one vulnerability. Using CWE to declare the problem leads to CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. Impacted is availability. The summary by CVE is:

TLS 1.3 embeds the actual record type as the last non-zero byte of the decrypted payload, optionally followed by zero padding. The code which searches for the inner record type had an off-by-one bug which could be triggered by an invalid frame, leading to an underflow followed by an unconditional NULL pointer dereference, causing a kernel panic. A remote TLS 1.3 peer can send a specially crafted record to trigger a kernel panic, resulting in a Denial of Service (DoS).

It is possible to read the advisory at security.freebsd.org. The identification of this vulnerability is CVE-2026-101302 since 09/28/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/15/2026).

Applying the patch p1/p4/p10/p14 is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-101870). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Operating System

Name

FreeBSD

License

open-source

Website

Product: https://www.freebsd.org/

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.2

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: p1/p4/p10/p14

Timelineinfo

09/28/2026 CVE reserved
10/15/2026 +17 days Advisory disclosed
10/15/2026 +0 days VulDB entry created
10/15/2026 +0 days VulDB entry last update

Sourcesinfo

Product: freebsd.org

Advisory: security.freebsd.org
Status: Confirmed

CVE: CVE-2026-101302 (🔒)
GCVE (CVE): GCVE-0-2026-101302
GCVE (VulDB): GCVE-100-420503
EUVD: 🔒

Entryinfo

Created: 10/15/2026 09:20
Updated: 10/15/2026 11:57
Changes: 10/15/2026 09:20 (53), 10/15/2026 11:57 (1)
Complete: 🔍
Cache ID: 216::103