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Fencer Vulns
medium 5.3

CVE-2026-2016 json

happyfish100 libfastcommon base64.c base64_decode stack-based overflow

published 2026-02-06 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-5685

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

A security vulnerability has been detected in happyfish100 libfastcommon up to 1.0.84. Affected by this vulnerability is the function base64_decode of the file src/base64.c. The manipulation leads to stack-based buffer overflow. Local access is required to approach this attack. The exploit has been disclosed publicly and may be used. The identifier of the patch is 82f66af3e252e3e137dba0c3891570f085e79adf. Applying a patch is the recommended action to fix this issue.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/happyfish100/libfastcommon/issues/55#issue-3836362577 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/happyfish100/libfastcommon/issues/55 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/happyfish100/libfastcommon/issues/55#issuecomment-3776757848 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 4.8 CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
CNA 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
CNA 3.0 5.3 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
CNA 2.0 4.3 AV:L/AC:L/Au:S/C:P/I:P/A:P/E:POC/RL:OF/RC:C
CNA 4.0 1.9 CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 2.0 4.3 AV:L/AC:L/Au:S/C:P/I:P/A:P

Affected products

  • happyfish100 libfastcommon

Classification

Weakness
  • CWE-121 Stack-based Buffer Overflow
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.