CVE-2026-42009

CVE-2026-42009 is a high-severity vulnerability in Redhat Hardened Images with a CVSS 3.x base score of 7.5. 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-475.

Key facts

Description

A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.

Frequently asked questions

What is CVE-2026-42009?
A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.
How severe is CVE-2026-42009?
CVE-2026-42009 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-42009 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42009?
CVE-2026-42009 primarily affects Redhat Hardened Images. In total, 43 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42009?
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.
Does CVE-2026-42009 have an EU (EUVD) identifier?
Yes. CVE-2026-42009 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30769.
When was CVE-2026-42009 published?
CVE-2026-42009 was published on 2026-05-18 and last updated on 2026-08-21.

References

Affected products (43)

More vulnerabilities in Redhat Hardened Images

All CVEs affecting Redhat Hardened Images →

Other CWE-475 vulnerabilities

Browse all CWE-475 vulnerabilities →