CVE-2026-114655 — KMS request injection via unsanitized key vault and provider values in libmongocrypt
libmongocrypt builds requests to external key management services (AWS, Azure and GCP) by inserting values from key vault documents, KMS provider configuration and KMS responses into request lines, headers and signed request bodies without validating or encoding them for each context. A user with write access to the key vault collection can alter the structure of these requests, including adding members to request bodies and token claims that the library then signs with the application's credentials. This may result in key management operations being performed with parameters the application did not intend.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.3% (30-day exploitation probability)+3
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Mongodb Libmongocrypt).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Mongodb | Libmongocrypt | ≥ 1.0.0 and < 1.21.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 6.0 | CVSS 4.0 | Medium | — | — | cna@mongodb.com via NIST National Vulnerability Database |
| 6.0 | CVSS 4.0 | Medium | — | — | mongodb via CVE Program (cve.org) e CISA ADP |
| 5.9 | CVSS 3.1 | Medium | 1.6 | 4.2 | cna@mongodb.com via NIST National Vulnerability Database |
| 5.9 | CVSS 3.1 | Medium | — | — | mongodb via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N (score shown at the top: cna@mongodb.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 23, 2026 → Oct 27, 2026 · 5 reading(s) · max 0.27%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Look for parameters with command/query metacharacters and unexpected child processes of the service.
Timeline
What happened to this CVE, newest first.
- 2026
- Source status changed · Received → Awaiting Analysis
- Affected products added · mongodb/libmongocrypt
- Record published
- CVSS changed · 5.9
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 22, 2026 – Oct 22, 2026
- 1× Official description updated · Oct 22, 2026 – Oct 22, 2026
References
3 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-106433 Heap corruption via duplicate masterKey fields in MongoDB libmongocrypt 19d
- Medium CVE-2026-106434 Unrecognized payload acceptance in explicit decryption in MongoDB libmongocrypt 19d
- Medium CVE-2026-106429 Application denial of service via malformed KMS endpoint in MongoDB libmongocrypt 19d
- Medium CVE-2026-84962 Authenticated KMS request forgery via CRLF injection in GCP key identifier strings Sep 3, 2026
- Medium CVE-2026-84971 Persistent client crash loop via undersized FLE2 insert-update ciphertext in decryption path Sep 3, 2026
- Medium CVE-2026-81523 Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt Aug 27, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-114655 is "KMS request injection via unsanitized key vault and provider values in libmongocrypt", rated Medium. It affects Libmongocrypt (Mongodb); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. EPSS 0.27% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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