CVE-2026-1979

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Source
https://cve.org/CVERecord?id=CVE-2026-1979
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1979.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-1979
Downstream
Published
2026-02-06T04:32:09Z
Modified
2026-08-12T15:31:36Z
Severity
  • 1.9 (Low) CVSS_V4 - 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 CVSS Calculator
Summary
mruby JMPNOT-to-JMPIF Optimization vm.c mrb_vm_exec use after free
Details

A flaw has been found in mruby up to 3.4.0. This affects the function mrb_vm_exec of the file src/vm.c of the component JMPNOT-to-JMPIF Optimization. Executing a manipulation can lead to use after free. The attack needs to be launched locally. The exploit has been published and may be used. This patch is called e50f15c1c6e131fa7934355eb02b8173b13df415. It is advisable to implement a patch to correct this issue.

Database specific 
{
    "cna_assigner": "VulDB",
    "cwe_ids": [
        "CWE-119",
        "CWE-416"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/1xxx/CVE-2026-1979.json"
}
References

Affected packages

Git / github.com/mruby/mruby

Affected ranges

Type
GIT
Repo
https://github.com/mruby/mruby
Events
Introduced
0f45836b5954accf508f333f932741b925214471
Last Affected
a309524d0bc90eef077a24634db2495a6f68e318
Database specific
Show details 
{
    "cpe": "cpe:2.3:a:mruby:mruby:*:*:*:*:*:ruby:*:*",
    "extracted_events": [
        {
            "introduced": "3.0"
        },
        {
            "last_affected": "3.0"
        },
        {
            "introduced": "3.1"
        },
        {
            "last_affected": "3.1"
        },
        {
            "introduced": "3.2"
        },
        {
            "last_affected": "3.2"
        },
        {
            "introduced": "3.3"
        },
        {
            "last_affected": "3.3"
        },
        {
            "introduced": "3.4.0"
        },
        {
            "last_affected": "3.4.0"
        },
        {
            "introduced": "0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ]
}
Type
GIT
Repo
https://github.com/sysfce2/mruby
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
e50f15c1c6e131fa7934355eb02b8173b13df415
Database specific
Show details 
{
    "source": "REFERENCES"
}

Affected versions

1.*
1.0.0
1.1.0
1.2.0
3.*
3.0
3.0.0-preview
3.1
3.2
3.3
3.4.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1979.json"
vanir_signatures 
[
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "309700451298586127084147669564925157237",
                "206465718435458731545810550109385677489",
                "232266857713372375953676997730443733663",
                "120459724042526479545393141050980971602",
                "88368804593802825400990602459277649762"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-1979-19a22880",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/sysfce2/mruby/commit/e50f15c1c6e131fa7934355eb02b8173b13df415",
        "target": {
            "file": "mrbgems/mruby-compiler/core/codegen.c"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "function_hash": "60665796433931384598915782097009808259",
            "length": 9440
        },
        "id": "CVE-2026-1979-82aaa20e",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/sysfce2/mruby/commit/e50f15c1c6e131fa7934355eb02b8173b13df415",
        "target": {
            "file": "mrbgems/mruby-compiler/core/codegen.c",
            "function": "codegen"
        }
    }
]
vanir_signatures_modified 
"2026-08-12T15:31:36Z"