CVE-2026-120678: MongoDB C Driver leaks the decompressed reply buffer when an OP_COMPRESSED reply fails to parse (denial of service)
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-11 15:49 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
A memory management flaw in the MongoDB C Driver’s handling of compressed responses may cause the client library to hold on to memory that is never released. An unauthenticated party that controls the database endpoint a client application connects to may cause repeated, unbounded memory growth in that application, which may result in the application becoming unavailable. No credentials, transport security settings, or user interaction are required.
Description quoted from the CVE record (assigned by mongodb, published 2026-11-03).
Weakness: CWE-401: Missing Release of Memory after Effective Lifetime
How it can be exploited
Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and no user interaction. Impact: confidentiality none, integrity none, availability high. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: yes. Technical impact: partial.
Public exploit evidence (Exploit Observer)
Exploit Observer has no public exploit code naming this CVE. Check Exploit Observer for anything new.
Live scores
- EPSS
- 0.004
low predicted chance of attack - VEDAS
- 0.047
little exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| MongoDB C Driver | from 1.25.0 up to and including 1.30.14 from 2.0.0 up to and including 2.5.7 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
Advisories on this CVE
References
Other references
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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