Heap overflow via 32-bit length wrap of the URI username in Windows Kerberos auth message wrapping

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.

A 32-bit integer wraparound in the MongoDB C Driver's Windows-only Kerberos/SSPI authentication code can cause an undersized heap buffer to be allocated when an excessively long credential value is supplied in the client's connection configuration. A party able to control that client-side configuration, in conjunction with the affected authentication mechanism, can cause the driver to write outside the bounds of the allocated buffer. This may result in corruption of client process memory and denial of service of the client application. The issue affects only client builds compiled with the Windows-native authentication backend.

Source published

22 Oct 2026 19:13:49 UTC

Source modified

29 Oct 2026 01:52:06 UTC

Observed here

29 Oct 2026 03:25:09 UTC

Source terms

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CVSS 4.0 · 5.7 CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

CVSS 3.1 · 5.2 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H