Linux Kernel up to 6.19.5 netfilter xt_tcpmss.c out-of-bounds

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.
3.4$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 6.19.5. The impacted element is an unknown function of the file net/netfilter/xt_tcpmss.c of the component netfilter. Performing a manipulation results in out-of-bounds. This vulnerability is reported as CVE-2026-43190. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 6.19.5. This affects an unknown functionality of the file net/netfilter/xt_tcpmss.c of the component netfilter. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_tcpmss: check remaining length before reading optlen Quoting reporter: In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads op[i+1] directly without validating the remaining option length. If the last byte of the option field is not EOL/NOP (0/1), the code attempts to index op[i+1]. In the case where i + 1 == optlen, this causes an out-of-bounds read, accessing memory past the optlen boundary (either reading beyond the stack buffer _opt or the following payload).

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-43190 since 05/01/2026. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 317729 (SUSE SLES12 Security Update : kernel (SUSE-SU-2026:2068-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16 or 6.19.6 eliminates this vulnerability. Applying the patch f895191dc32c53eaf443b6443fe40945b2f92287/cd5beda7e0e32865e214f28034bb92c1cecff885/eaedc0bc18be46fe7f58170e967959a932c4f824/07a9b32eaae792ff7d0fcac14d8920c937c0a9c3/8b300f726640c48c3edfe9c453334dd801f4b74e/5e13d0a37666955b6cfddc0f73cb40ed645b8a05/f6c412dcfd76b0516d51aa847d8f4c7b70381b09/735ee8582da3d239eb0c7a53adca61b79fb228b3 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (317729). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.5
VulDB Meta Temp Score: 3.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 317729
Nessus Name: SUSE SLES12 Security Update : kernel (SUSE-SU-2026:2068-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.252/5.15.202/6.1.165/6.6.128/6.12.75/6.18.16/6.19.6
Patch: f895191dc32c53eaf443b6443fe40945b2f92287/cd5beda7e0e32865e214f28034bb92c1cecff885/eaedc0bc18be46fe7f58170e967959a932c4f824/07a9b32eaae792ff7d0fcac14d8920c937c0a9c3/8b300f726640c48c3edfe9c453334dd801f4b74e/5e13d0a37666955b6cfddc0f73cb40ed645b8a05/f6c412dcfd76b0516d51aa847d8f4c7b70381b09/735ee8582da3d239eb0c7a53adca61b79fb228b3

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
05/30/2026 +24 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43190 (🔒)
GCVE (CVE): GCVE-0-2026-43190
GCVE (VulDB): GCVE-100-361467

Entryinfo

Created: 05/06/2026 16:49
Updated: 05/30/2026 14:41
Changes: 05/06/2026 16:49 (59), 05/30/2026 14:41 (2)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you want to use VulDB in your project?

Use the official API to access entries easily!