Buffer overflow in Janet-Lang Janet
CVE-2026-2240
A vulnerability has been found in janet-lang janet up to 1.40.1. The impacted element is the function janetc_pop_funcdef of the file src/core/compile.c. Such manipulation leads to out-of-bounds read. The attack must be carried out locally. The exploit has been disclosed to the public and may be used. The name of the patch is 4dd08a4cdef5b1c42d9a2c19fc24412e97ef51d5. A patch should be applied to remediate this issue.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (5.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Janet-Lang Janet — versions 1.40.0, 1.40.1
Weakness classification (CWE)
References
- vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
- vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
- vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
- github.com/janet-lang/janet/issues/1702 (issue-tracking, Exploit, Issue Tracking)
- github.com/janet-lang/janet/issues/1702 (issue-tracking, Exploit, Issue Tracking)
- github.com/oneafter/0123/blob/main/ja4/repro (Exploit, exploit)
- github.com/janet-lang/janet/commit/4dd08a4cdef5b1c42d9a2c19fc24412e97ef51d5 (Patch, patch)
- github.com/janet-lang/janet/ (Product, product)
Frequently asked questions
- What is CVE-2026-2240?
- CVE-2026-2240 is a low-severity vulnerability in Janet-Lang Janet, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 3.3/10. Published 2026-02-09.
- How severe is CVE-2026-2240?
- Low severity. CVSS v3 base score is 3.3 out of 10.