How severe is CVE-2026-18511?

CVE-2026-18511 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-18511 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-18511?

CVE-2026-18511 primarily affects Ibm I. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-18511?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-18511 published?

CVE-2026-18511 was published on 2026-08-13 and last updated on 2026-08-17.

CVE-2026-18511

CVE-2026-18511 is a high-severity vulnerability in Ibm I with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.3)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Ibm I
Published: 2026-08-13
Last modified: 2026-08-17

Description

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.

Frequently asked questions

What is CVE-2026-18511?: 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.
How severe is CVE-2026-18511?: CVE-2026-18511 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-18511 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-18511?: CVE-2026-18511 primarily affects Ibm I. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-18511?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-18511 published?: CVE-2026-18511 was published on 2026-08-13 and last updated on 2026-08-17.

References

https://www.ibm.com/support/pages/node/7283285

Affected products (4)

cpe:2.3:a:ibm:i:7.3:*:*:*:*:*:*:*
cpe:2.3:a:ibm:i:7.4:*:*:*:*:*:*:*
cpe:2.3:a:ibm:i:7.5:*:*:*:*:*:*:*
cpe:2.3:a:ibm:i:7.6:*:*:*:*:*:*:*

More vulnerabilities in Ibm I

CVE-2026-16860 — Critical (CVSS 9.9): IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to execute arbitrary code due to an…
CVE-2026-17083 — Critical (CVSS 9.8): IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to execute arbitrary code due to a stack-based buffer…
CVE-2026-17218 — Critical (CVSS 9.8): IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to execute arbitrary code due to an out-of-bounds write.
CVE-2026-17276 — Critical (CVSS 9.6): IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to escalate privileges due to improper…
CVE-2026-18193 — High (CVSS 8.9): IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to bypass security restrictions due to improper validation…
CVE-2026-18099 — High (CVSS 8.9): IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to execute arbitrary script code due to…

All CVEs affecting Ibm I →

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