JITServer: Pre-authentication remote crash via integer underflow and out-of-bounds heap read in DataDescriptor deserialization

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

In Eclipse OpenJ9 versions prior to 0.63.0, the JITServer component fails to perform cross-field validation on attacker-controlled `_size`, `_paddingSize`, and `_dataOffset` fields during `DataDescriptor` message deserialization. An unauthenticated remote attacker can send a crafted network payload that triggers an unsigned integer underflow in `DataDescriptor::getPayloadSize()` and `DataDescriptor::getNextDescriptor()`. This results in an out-of-bounds heap read and an immediate process crash (SIGSEGV), causing a denial of service.

Source published

21 Oct 2026 08:00:32 UTC

Source modified

26 Oct 2026 17:57:34 UTC

Observed here

26 Oct 2026 18:35:30 UTC

Source terms

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CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N