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Fencer Vulns
low 2.5

CVE-2026-2655 json

ChaiScript chaiscript_defines.hpp operator use after free

published 2026-02-18 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-7647

cvss
2.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

A vulnerability was detected in ChaiScript up to 6.1.0. The impacted element is the function chaiscript::str_less::operator of the file include/chaiscript/chaiscript_defines.hpp. The manipulation results in use after free. The attack requires a local approach. The attack requires a high level of complexity. The exploitability is regarded as difficult. The exploit is now public and may be used. The project was informed of the problem early through an issue report but has not responded yet.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ChaiScript/ChaiScript/issues/632 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/ChaiScript/ChaiScript/issues/632#issue-3827824936 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 2.0 CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CNA 3.1 2.5 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA 3.0 2.5 CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA 2.0 1.0 AV:L/AC:H/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR
CNA 4.0 1.1 CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/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 2.5 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
CNA 2.0 1.0 AV:L/AC:H/Au:S/C:N/I:N/A:P

Affected products

  • n/a ChaiScript

Classification

Weakness
  • CWE-416 Use After Free
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

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.