CVSS 4.0
5.6 mediumCVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:NCVE-2026-126792
Heap overflow via oversized RSA signature in GCP KMS signing callback
Medium (5.6) in mongodb libmongocrypt driver.
A memory-safety flaw in the key-management request-building component of the library can lead to an out-of-bounds write on the heap. A fixed-size output buffer is used under an assumption about cryptographic key size that is never validated, so when the library is embedded by a caller that supplies its own cryptographic callback implementation, data larger than the buffer can be written past its end. Exploitation requires the ability to control the embedding application's in-process key-management provider configuration, a high-privilege position. The demonstrated impact is memory corruption resulting in abnormal termination of the client process.
Severity
CVSS 3.1
4.7 mediumCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H- CWE
- CWE-787 Out-of-bounds Write
- Published
- Assigned by
- mongodb (CNA)
- NVD analysis
- Not in the NVD yet
- Record from
- the CVE List, synced
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Affected
- mongodb:libmongocrypt driver
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| MongoDB Libmongocrypt Driver | from 1.1.0 through 1.21.2 |