Security readout for executives and security teams
Plain-English summary
Mongoose-OS 2.17.0 has an integer wraparound in its memory allocator. In plain terms, a size calculation can go wrong and allocate memory incorrectly. The sources say this can cause crashes or potentially remote code injection or execution. The issue is high severity because it is network-reachable and does not require authentication or user interaction.
Executive priority
Prioritize remediation for internet-facing or operationally critical systems using Mongoose-OS v2.17.0. The issue can affect availability and may affect confidentiality and integrity, but evidence of active exploitation is not provided in the source bundle.
Technical view
CVE-2021-27425 is CWE-190 in Cesanta Software Mongoose-OS v2.17.0, affecting mm_malloc. The CVSS 3.1 vector is AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L, score 7.3. The described impact is improper memory assignment leading to unexpected behavior, crash, or remote code injection/execution.
Likely exposure
Exposure is limited to systems running or embedding Cesanta Software Mongoose-OS v2.17.0. Network-accessible deployments are the main concern based on the CVSS vector. The source bundle does not identify other affected versions, downstream products, or specific deployment scenarios.
Exploitation context
The source bundle supports unauthenticated, low-complexity, network-reachable risk. It does not show CISA KEV listing or provide evidence of active exploitation. Treat exploitation status as unconfirmed, not active, unless newer vendor or government guidance says otherwise.
Researcher notes
The key evidence is the vulnerable mm_malloc allocator path, CWE-190 classification, and high CVSS network vector. Sources do not name a patch level, exploitation in the wild, or downstream products. Avoid broad product claims without confirming actual Mongoose-OS v2.17.0 presence.
Mitigation direction
- Identify and prioritize Mongoose-OS v2.17.0 assets or embedded dependencies.
- Check Cesanta and CISA guidance for the recommended fixed version or mitigation.
- Restrict network access to affected services until remediation is confirmed.
- Monitor affected systems for crashes or unexpected behavior.
- Validate any vendor update in staging before production rollout.
Validation and detection
- Confirm whether Mongoose-OS v2.17.0 is present in firmware, SBOMs, or source dependencies.
- Map which affected instances are reachable over a network.
- Review vendor advisories for version-specific remediation details.
- Check logs and uptime history for crashes around affected components.
- Document compensating controls where immediate update is unavailable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-190: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-27425 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cisa.gov/uscert/ics/advisories/icsa-21-119-04CVE reference · x_refsource_CONFIRM
- https://github.com/cesanta/mongoose-osCVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Integer Overflow or Wraparound
Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.