Fixed values in MongoDB Server $bucket stage may be misread as field references

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.

An issue in MongoDB Server's aggregation framework can cause certain constant values to be handled incorrectly during internal query rewriting. Under certain conditions, an authenticated user with read access may receive field values in aggregation output that the query did not intend to return.

Source published

13 Oct 2026 15:33:20 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 · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS 3.1 · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N