CVE-2026-84971
CVE-2026-84971 is a medium-severity vulnerability in Mongodb Libmongocrypt with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-617.
Key facts
- Severity: Medium (CVSS 3.x base score 6.5)
- CVSS v4: 7.1
- EPSS exploit prediction: 0% (16th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-617
- Affected product: Mongodb Libmongocrypt
- Published:
- Last modified:
Description
Improper handling of an unexpected value size in the decryption path of a client-side encryption library can cause a failed internal check that terminates the process using the library. A party able to place a suitably formed encrypted value where an application will decrypt it, or able to control the responses the application receives, may cause that application to stop running.
Frequently asked questions
- What is CVE-2026-84971?
- Improper handling of an unexpected value size in the decryption path of a client-side encryption library can cause a failed internal check that terminates the process using the library. A party able to place a suitably formed encrypted value where an application will decrypt it, or able to control the responses the application receives, may cause that application to stop running.
- How severe is CVE-2026-84971?
- CVE-2026-84971 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-84971 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-84971?
- CVE-2026-84971 affects Mongodb Libmongocrypt. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-84971?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2026-84971 published?
- CVE-2026-84971 was published on 2026-09-03 and last updated on 2026-09-17.
References
Affected products (1)
- cpe:2.3:a:mongodb:libmongocrypt:*:*:*:*:*:*:*:*
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