MongoDB Server may disclose process memory via a crafted `$_internalApplyOplogUpdate` aggregation pipeline

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.

Use of freed memory in the aggregation feature of MongoDB Server can cause the server to read data from a memory area after it has been released. When an internal aggregation stage is combined with a batch size of 0, the server may read from memory that is no longer in use. Because that memory can be reused for other data before it is read, query results returned to the client may contain unrelated data from the server process. Depending on the state of memory at the time, the server process may also terminate unexpectedly. The behavior can occur when an authenticated user with read privileges runs an aggregate command that combines these two settings.

Source published

13 Oct 2026 15:23:57 UTC

Source modified

13 Oct 2026 16:20:06 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N