VDB-389876 · CVE-2026-18511 · GCVE-0-2026-18511

IBM i 7.3/7.4/7.5/7.6 Native IBM i JSSE Provider stack-based overflow

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.
8.8	$5k-$25k	1.51

Summaryinfo

A vulnerability was found in IBM i 7.3/7.4/7.5/7.6 and classified as very critical. This vulnerability affects unknown code of the component Native IBM i JSSE Provider. Such manipulation leads to stack-based overflow. This vulnerability is documented as CVE-2026-18511. The attack needs to be performed locally. There is not any exploit available.

Detailsinfo

A vulnerability was found in IBM i 7.3/7.4/7.5/7.6 and classified as very critical. Affected by this issue is an unknown code of the component Native IBM i JSSE Provider. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. CVE summarizes:

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local authenticated attacker to generate a stack-based buffer overflow in the Native IBM i JSSE provider, caused by improper bounds checking during TLS session establishment. A local attacker could overflow a fixed-length buffer and execute arbitrary code on the system or cause the JVM process to crash.

The advisory is shared for download at ibm.com. This vulnerability is handled as CVE-2026-18511 since 07/31/2026. The exploitation is known to be easy. The attack needs to be approached locally. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 08/13/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

License

commercial

Website

Vendor: https://www.ibm.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.8

VulDB Base Score: 8.8
VulDB Temp Score: 8.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

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

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

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
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: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/31/2026 CVE reserved
08/13/2026 +13 days Advisory disclosed
08/13/2026 +0 days VulDB entry created
08/13/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: ibm.com

Advisory: ibm.com
Status: Confirmed

CVE: CVE-2026-18511 (🔒)
GCVE (CVE): GCVE-0-2026-18511
GCVE (VulDB): GCVE-100-389876

Entryinfo

Created: 08/13/2026 23:06
Changes: 08/13/2026 23:06 (53)
Complete: 🔍
Cache ID: 216::103