Security readout for executives and security teams
Plain-English summary
TencentOS-tiny 3.1.0 has a memory allocation flaw. A bad size calculation can wrap around and allocate the wrong amount of memory, causing crashes or potential remote code execution. This matters most where TencentOS-tiny is embedded in exposed devices or operational technology systems.
Executive priority
High priority for environments with TencentOS-tiny in network-exposed or operational devices. Confirm exposure first, because the public sources name the OS version but not specific downstream products.
Technical view
CVE-2021-27439 is a CWE-190 integer wrap-around in TencentOS-tiny 3.1.0, in tos_mmheap_alloc effective allocation size calculation. The CVSS 3.1 score is 7.3 with network attack vector, low complexity, no privileges, and no user interaction.
Likely exposure
Likely exposure is embedded, IoT, or ICS-adjacent products running TencentOS-tiny 3.1.0. The bundle does not identify downstream device models or products, so asset inventory and firmware provenance are required.
Exploitation context
The CVSS vector indicates remotely reachable attack conditions are possible. The provided sources do not state active exploitation, and KEV status is false. Treat exploit status as unconfirmed, not absent.
Researcher notes
Evidence supports the affected version, vulnerability class, impacted function, and CVSS vector. The bundle does not provide patch version, exploit proof, or downstream affected product mapping, so avoid assuming fix status or device scope.
Mitigation direction
- Identify assets or firmware using TencentOS-tiny 3.1.0.
- Check TencentOS-tiny and CISA guidance for confirmed fixes or mitigations.
- Reduce network exposure for affected embedded or OT devices.
- Prioritize vendor-supported firmware updates when available.
- Monitor affected devices for unexplained crashes or restarts.
Validation and detection
- Review SBOMs, firmware manifests, and vendor notices for TencentOS-tiny 3.1.0.
- Confirm whether exposed services can reach TencentOS-tiny heap allocation paths.
- Check device logs for crashes, resets, or memory fault indicators.
- Track CISA and CVE updates for downstream product details.
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-2021-27439 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
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.