9.8

CVE-2021-27439: TencentOS-tiny Integer Overflow or Wraparound

Modified
Published 03-05-2022Last modified 16-04-2025

Vulnerability summary

CVE-2021-27439 is a critical (CVSS 9.8) Integer Overflow or Wraparound vulnerability in tencent tencentos-tiny. EPSS estimates a 1.56% chance of exploitation in the next 30 days, higher than 75.2% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.3 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 2% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
1.56%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 03-05-2022
    PublishedVulnerability first disclosed.
  2. 16-04-2025
    Last modifiedVulnerability information updated.

Description

TencentOS-tiny version 3.1.0 is vulnerable to integer wrap-around in function 'tos_mmheap_alloc incorrect calculation of effective memory allocation size. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

1.56%

Chance of exploitation in the next 30 days

Percentile

75%

Versus all other CVEs

30-day change

No change 0.00 pp

From 1.56% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Tencent1 product
Tencentos-tiny1 product

2 vendors · 2 products

References

1 links