MongoDB CVE-2025-14847: High Impact Memory Disclosure Under KEV Spotlight

CISA says it has added one new vulnerability to its Known Exploited Vulnerabilities (KEV) Catalog — a MongoDB flaw tracked as CVE‑2025‑14847 — but independent public records show the underlying bug, vendor fixes, and active‑exploitation reports are better documented than the specific KEV entry itself, so organizations should treat the technical facts as confirmed, and CISA’s catalog status as operationally important but worth double‑checking against the KEV entry in each environment.

Background / Overview​

The Cybersecurity and Infrastructure Security Agency’s Known Exploited Vulnerabilities (KEV) Catalog was created under Binding Operational Directive (BOD) 22‑01 to convert evidence of in‑the‑wild exploitation into an operational remediation mandate for Federal Civilian Executive Branch (FCEB) agencies. When CISA places a CVE on KEV it signals that there is credible exploitation evidence and sets a remediation timeline for federal agencies; the KEV list is widely used as a high‑priority signal by enterprise vulnerability managers outside government as well. On or around late December 2025 multiple security vendors and tracking services disclosed and analyzed a serious MongoDB bug — CVE‑2025‑14847 — described as an Improper Handling of Length Parameter Inconsistency in MongoDB’s handling of zlib‑compressed protocol headers. Public vulnerability databases and vendor issue trackers show the underlying technical root cause, the broad version impact, and the patched versions; independent reporting indicates active exploitation activity and urges immediate remediation. This article explains what the bug is, who’s affected, why it matters for Windows‑centric and mixed enterprise environments, and what immediate and medium‑term remediation and detection steps defenders should take. Where CISA’s KEV catalog entry could not be directly retrieved at the time of reporting, that specific point is flagged as not independently verifiable here; the vulnerability itself, vendor fixes, and exploit telemetry are corroborated by multiple independent sources and vendor advisories.

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What CVE‑2025‑14847 is — the technical summary​

The root cause in plain terms​

• The vulnerability stems from mismatched length fields in zlib‑compressed protocol headers used by MongoDB’s wire protocol. When the server parses compressed frames it can trust a declared length that does not match the actual compressed payload and, under certain conditions, read uninitialized heap memory and return portions of that memory over the network to an unauthenticated client. This is classed as CWE‑130: Improper Handling of Length Parameter Inconsistency.
• Practically, the attack vector is network‑facing and unauthenticated — an attacker only needs TCP access to a MongoDB server instance that accepts compressed messages. That means internet‑reachable database ports, or poorly segmented internal networks, are the highest‑exposure targets.

What it can expose or enable​

• The immediate, demonstrable impact is confidentiality loss: arbitrary portions of server process memory may be leaked. Those memory contents can include credentials, tokens, or other sensitive plaintexts resident in RAM at the time of the leak.
• Memory‑leak vulnerabilities are often an initial disclosure/footprint that can be chained to achieve further compromises (for example, leaking key material that then enables authentication bypass), and in some cases memory disclosure bugs can be weaponized into remote code execution (RCE) depending on how an attacker manipulates the leaked data and the target environment. Several vendor and third‑party writeups note that the bug’s classification and exploitation potential makes it a serious, high‑priority remediation item.

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Affected products and patched versions​

MongoDB’s issue tracker and independent vulnerability databases list the affected lines and the minimum patched versions. In short, the flaw is broadly present across many supported and legacy MongoDB Server and MongoDB binary lines; vendor patches are available for all currently supported branches. Key remediation versions published by vendors and trackers include:

• Upgrade to MongoDB 8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, or 4.4.30 (or later) which contain the fix for CVE‑2025‑14847.
• Vulnerable ranges reported across trackers include:
• MongoDB 8.2.0 — 8.2.2 (fixed in 8.2.3)
• MongoDB 8.0.0 — 8.0.16 (fixed in 8.0.17)
• MongoDB 7.0.0 — 7.0.27 (fixed in 7.0.28)
• MongoDB 6.0.0 — 6.0.26 (fixed in 6.0.27)
• MongoDB 5.0.0 — 5.0.31 (fixed in 5.0.32)
• MongoDB 4.4.0 — 4.4.29 (fixed in 4.4.30)
• All MongoDB Server v4.2, v4.0 and v3.6 versions are noted as affected in vendor trackers and advisories until their maintenance lines are upgraded.

If an organization manages multiple maintenance streams — particularly those retained for legacy applications — the inventory and patch mapping step must be explicit and immediate.

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Evidence of active exploitation and CISA’s KEV status​

Multiple cybersecurity news outlets and threat intelligence trackers reported that CVE‑2025‑14847 was being actively exploited in the wild shortly after disclosure and that vendors issued emergency advisories and patches. Those reports cite observed exploitation and urgent vendor guidance to upgrade immediately or implement mitigations where immediate patching is not possible. Regarding CISA specifically: the user‑supplied CISA alert text indicates a KEV addition; however, a direct retrieval of the exact CISA KEV item for CVE‑2025‑14847 from the public KEV catalog page could not be conclusively located at time of reporting, and therefore that specific operational claim should be double‑checked directly against the CISA KEV catalog page and the agency’s alert archive. Treat the CISA KEV claim as operationally important and plausibly accurate given the pattern of rapid KEV additions for actively exploited flaws, but verify the KEV entry date and remediation due date in your compliance tracking tools. If CISA has indeed placed CVE‑2025‑14847 on KEV, federal agencies will be subject to BOD 22‑01 remediation timelines. (Operational note: KEV additions frequently follow confirmed exploitation or large‑scale scanning/weaponization; KEV placement matters for compliance but does not change the technical urgency: the vulnerability and vendor fixes exist regardless of catalog placement.

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Practical immediate steps for defenders (what to do now)​

If you operate MongoDB infrastructure — cloud‑hosted or self‑managed — treat this as an emergency triage item. The following checklist summarizes prioritized actions:

• Inventory and identify
• Scan and enumerate all MongoDB server instances (including older on‑prem instances, container images, and cloud DB‑as‑a‑service endpoints under your control).
• Identify exposed endpoints (internet‑facing IPs, security group rules) and application‑tier connections that could reach the DB port.
• Patch or mitigate immediately
• Apply vendor recommended upgrades to the patched versions listed above, following your change control and test‑staging procedures.
• If immediate upgrades are not possible, implement temporary mitigations (see #3). Snyk and vendor trackers explicitly list the pinned upgrade targets and the urgency to update.
• Short‑term mitigations if you cannot patch immediately
• Disable zlib compression to remove the attack surface: configure mongod/mongos to omit zlib from the net.compression.compressors (or use the appropriate startup flag on older builds). Several CERTs and security advisories recommend this as an interim control.
• Reduce exposure: restrict inbound network access to database ports using firewalling, cloud security groups, and host‑based ACLs so only authorized application servers may connect.
• Apply egress and ingress network logging and temporary rate limiting where possible to increase detection opportunities.
• Hunt and detect
• Review historical network and application logs for unusual or repeated connections to MongoDB ports from unknown IPs, especially around the disclosure window.
• Search for evidence of anomalous responses from mongod that carry unexpected content or binary blobs (memory leakage may appear as anomalous or non‑protocol data).
• Use IDS / EDR detection rules and threat intel feeds; vendors and threat centers began issuing IOCs and scanning indicators shortly after the disclosure.
• Post‑patch validation and monitoring
• After upgrading, validate service behavior under load and check logs for any signs of instability.
• Continue to monitor for exploitation attempts; active campaigns often intensify in the window following disclosure and KEV placement.

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Detection guidance — concrete signals to look for​

• Unusual connections from public IP blocks to MongoDB listener ports (typically TCP 27017 unless customized).
• Unexpected or malformed compressed frame payloads or elevated error counts in the server log related to compression parsing.
• Any outbound connections or data exfiltration patterns originating from the database host after discovery of suspicious inbound activity.
• Repeated successful unauthenticated protocol interactions that request compressed frames (an unauthenticated client abusing the compression parser is the core attack path).

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Why this class of bug is dangerous for enterprises​

Memory‑leak and uninitialized memory disclosure bugs create a stealthy, high‑value information vector: leaked memory can contain credentials, session tokens, private keys, or fragments that help an attacker chain into elevated privileges or pivot to other systems. Databases are high‑value targets because they aggregate sensitive enterprise data and secrets; an internet‑exposed database with a pre‑authentication memory disclosure is an immediate prime target for automated scanning and exploitation campaigns. That is why vendors, CERTs, and threat centers labeled this vulnerability high priority and recommended immediate patching.

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Operational and compliance implications​

• If CISA places a CVE on the KEV Catalog, FCEB agencies are legally required to remediate or apply compensating controls within the due date specified under BOD 22‑01. Even for non‑federal entities, KEV placement is an operational indicator used by CISOs and risk teams to accelerate patch windows and contract remediation deadlines with suppliers. Confirm the KEV entry and its remediation due date in your compliance trackers if you are a federal agency or contractor.
• For cloud providers and managed service providers that host MongoDB instances for customers, accelerated patch scheduling and coordinated notifications are required to avoid cross‑tenant compromise. Where providers manage patching, confirm timelines and ask for proof of remediation for affected tenants.

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Strengths and limitations of current public information​

• Strengths:
• Multiple high‑quality trackers and vendor issue pages document the bug’s technical root cause, affected versions, and the exact patched versions; NVD and the vendor’s Jira record provide authoritative identifiers and a CVSS rating. That makes technical triage and patch planning practical and immediate.
• Security press outlets and threat feeds reported active exploitation and provided practical mitigations that defenders could implement if they could not immediately upgrade.
• Limitations and caution:
• The user‑supplied CISA alert text asserts KEV catalog placement; however, at the time of writing a direct, retrievable CISA KEV page specifically referencing CVE‑2025‑14847 could not be located by the research toolchain. As a result, the catalog‑placement claim should be validated directly against CISA’s KEV page by compliance teams. This is an operational detail with regulatory weight, so do not assume the remediation deadline until the KEV entry is independently confirmed.
• Some early press pieces used strong language about RCE in specific hosting contexts — while memory disclosure can lead to RCE in some circumstances, whether it does depends on local process layout, allocator behavior, and the presence of exploitable primitives; the immediate, confirmed impact across public trackers is memory disclosure and information leakage and not universal guaranteed RCE. Treat RCE as a potential escalation path and plan accordingly, but base immediate actions on the confirmed information‑disclosure behavior.

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Recommended remediation playbook (concise, operational)​

• Immediate (hours)
• Map all MongoDB endpoints and block internet exposure except for approved app tiers.
• If feasible, schedule emergency patch windows and apply vendor‑released versions listed above.
• If patching cannot be completed within 24–72 hours, disable zlib compression and document the compensating control, while increasing logging/monitoring.
• Short term (days)
• Patch all affected instances and validate success.
• Conduct hunts for suspicious inbound scans or anomalous leak indicators.
• Rotate credentials, API keys, and any secrets that could have been resident in memory on exposed hosts if there’s evidence of suspicious activity.
• Medium term (weeks)
• Harden DB access controls: enforce network segmentation, mutual TLS for connections where supported, and principle of least privilege for database accounts.
• Integrate checks for protocol compression misuse into the application‑level tests and security acceptance criteria.
• Longer term (months)
• Review platform configuration to remove internet‑accessible direct database hosts — place databases behind application tiers or private networks and use secure service meshes or managed DB services with hardened access controls.
• Add memory‑sanitization reviews and fuzzing for protocol parsers to CI/CD vulnerability testing for critical server components.

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Final analysis and risk assessment​

CVE‑2025‑14847 is a high‑impact, high‑urgency vulnerability because:

• It is pre‑authentication and network‑accessible against older and current MongoDB server builds, which lowers the attacker’s bar for scanning and exploitation.
• It exposes server memory, making it valuable for attackers seeking credentials or cryptographic material that supports follow‑on compromise.
• Vendor patches are available for all supported versions, and documented mitigations (disable zlib compression) exist for those who cannot immediately patch.

From a defensive posture perspective, the combination of broad version coverage, unauthenticated attack vector, and reports of active exploitation justifies accelerating remediation windows, increasing monitoring, and treating any internet‑reachable MongoDB instance as compromised until proven otherwise.

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Closing notes​

• Confirm whether CISA’s KEV catalog explicitly lists CVE‑2025‑14847 and note the remediation due date for any federal compliance obligations; the KEV placement is operationally important but should be verified directly.
• For Windows‑centric organizations that use MongoDB as part of backend services or hybrid cloud stacks, prioritize:
• inventorying database endpoints,
• restricting network exposure,
• applying vendor patches, and
• rotating keys if there’s any sign of suspicious access.
• The vulnerability is a reminder that protocol parsing and compression remain recurring high‑value attack surfaces: treat protocol parsers in server software as critical security boundaries and include them in active fuzzing and memory‑safety testing.

CISA’s KEV mechanism and BOD 22‑01 exist to shorten the remediation window for the most dangerous, actively exploited bugs — whether or not the KEV entry for CVE‑2025‑14847 is immediately retrievable, the technical facts and vendor fixes are in the public domain and should be acted on now.

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Source: CISA CISA Adds One Known Exploited Vulnerability to Catalog | CISA